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Easy Algebra 2 - 2.6 function transformations

SVMathTeach · YouTube · 4:50

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This introductory Algebra 2 whiteboard clip defines a parent function, illustrates it with y=f(x)=x2y=f(x)=x^2, and lists common transformations of a function graph: horizontal and vertical shifts, reflections, and vertical stretches or compressions. It then works Example A in full, translating y=f(x)y=f(x) 4 units left and 3 units down to obtain y=f(x+4)−3y=f(x+4)-3. The speaker emphasizes the key rule that a left shift is written with plus inside the function argument. Examples B and C are shown on the board but are not solved within this segment. This introductory algebra whiteboard clip teaches how to rewrite y=f(x)y=f(x) under common transformations. It works through three examples: (A) translate 4 units left and 3 down to get y=f(x+4)−3y=f(x+4)-3; (B) translate 5 units right and reflect across the x-axis to get y=−f(x−5)y=-f(x-5); and (C) translate 5 units right and reflect across the y-axis to get y=f(−x−5)y=f(-x-5). The key rules emphasized are that horizontal shifts go inside the parentheses with the opposite sign, vertical shifts go outside the function, x-axis reflection negates the whole function, and y-axis reflection negates only x.

Use the learning inspector for key ideas and moments, or open the reading tabs for the complete notes.

Chapters

0:00Introduction to families of functions0:06Parent function definition and example0:30Types of transformations1:23Example A setup2:00Solving Example A: left 4, down 32:43Prompts for Examples B and C2:45Setup and part (B) horizontal shift3:23Reflection across the x-axis3:57Part (C) horizontal shift and y-axis reflection4:32Summary of transformation rules

Learning script

Generated from the video's visuals and explanation; not verbatim speech.

The clip opens on a digital whiteboard headed “2-6 Functions, Equations, and Graphs” with the subheading “FAMILIES OF FUNCTIONS.” The speaker introduces the topic as families of functions and immediately frames the lesson around a base object that will later be modified.

The first mathematical idea is the parent function. The speaker defines it verbally as “the simplest form of a function,” and the board reinforces this by writing the example y=f(x)=x2y=f(x)=x^2. A small upward-opening parabola is sketched beside the formula, visually connecting the algebraic rule to its standard graph.

Next, the lesson broadens from the single example to a classification of transformations. The handwritten outline names shifts left, right, up, and down; reflections; and vertical stretches plus compressions. In speech, the presenter explains that these operations move or reshape the graph of the parent function, including making it “skinnier and taller” or “shorter and kind of squatter.”

The speaker then transitions from definitions to practice, saying that three examples will stand in for a fuller textbook chart. The board scrolls to a worked-problem section labeled “(Ex) Write the equation for the transformation of the graph y=f(x)y=f(x),” followed by parts (A), (B), and (C). Only part (A) is actually solved in this segment.

Part (A) asks for the equation after translating the graph 4 units left and 3 units down. Before solving, the speaker highlights the main conceptual trap: intuitively, “left” suggests a negative coordinate, but that intuition does not directly determine the symbolic form inside the function.

The derivation proceeds from the base equation y=f(x)y=f(x). First, the horizontal translation is encoded inside the argument: because the shift is 4 units left, the speaker writes f(x+4)f(x+4) and explicitly states that left uses plus. This is the central rule emphasized in the clip.

Second, the vertical translation is handled outside the function. Moving 3 units down is represented by appending −3-3, yielding the final equation y=f(x+4)−3y=f(x+4)-3. The answer is boxed on the board, and the speaker identifies this boxed expression as the required equation for the transformed graph.

At the end of the segment, the board still shows the prompts for parts (B) and (C): “translate 5 units right, reflect across the x-axis” and “translate 5 units right, reflect across the y-axis.” The speaker begins to move on to letter B, but no solution for B or C is completed within the provided clip.

The clip opens on a digital whiteboard with three transformation prompts already written: (A) translate 4 units left, 3 down; (B) translate 5 units right, reflect across the x-axis; and (C) translate 5 units right, reflect across the y-axis. Part (A) is already completed as y=f(x+4)−3y=f(x+4)-3, which serves as a reference for the rules being discussed.

The instructor starts solving part (B) from the base relation y=f(x)y=f(x). Because the prompt says “5 units right,” he applies the horizontal-translation rule inside the argument and writes f(x−5)f(x-5). He explicitly stresses that the sign is opposite the intuitive direction: right corresponds to subtraction inside the parentheses.

He then separates the next operation from ordinary vertical shifting. While mentioning that up/down changes are simpler outside adjustments, he introduces reflection as a different kind of modification that requires a negative sign in a specific location.

For reflection across the x-axis, the explanation is that points on top flip to the bottom relative to the x-axis. This is reinforced by an orange sketch showing a curve above a horizontal line and its mirror image below the line. The algebraic consequence is to place a negative sign in front of the entire function, turning f(x−5)f(x-5) into −f(x−5)-f(x-5).

With part (B) finished, the board now displays the completed transformed equation y=−f(x−5)y=-f(x-5), boxed for emphasis. The instructor frames this as a preliminary step in the broader topic of function transformations.

He moves to part (C), noting that it is almost the same as part (B) except for the type of reflection. Again starting from y=f(x)y=f(x), he first applies the same horizontal shift of 5 units right, producing f(x−5)f(x-5).

For reflection across the y-axis, he says the negative sign must be introduced in a different place: only the input variable xx becomes negative. Thus the expression changes from f(x−5)f(x-5) to f(−x−5)f(-x-5), and the final boxed answer for part (C) is y=f(−x−5)y=f(-x-5).

The closing summary contrasts the rules directly: horizontal movement goes inside the parentheses with the opposite sign, vertical movement is handled outside the function, reflection across the x-axis negates the whole function, and reflection across the y-axis negates only xx inside the argument.

Knowledge cards

01

Parent function

A parent function is the simplest representative form of a family of functions. In this clip, the quadratic parent function is shown as y=f(x)=x2y=f(x)=x^2, and its basic graph is sketched as an upward-opening parabola.

y=f(x)=x2y=f(x)=x^2
02

Main transformation types

The lesson classifies transformations of a function graph into horizontal and vertical shifts, reflections, and vertical stretches or compressions. These are presented as operations performed on the parent function’s graph.

03

Horizontal shift rule

For a horizontal translation, the shift is inserted inside the function argument with xx. The clip specifically teaches that moving left by 4 units is written as x+4x+4, not as a minus sign in that position.

left 4:f(x)→f(x+4)\text{left }4:\quad f(x)\to f(x+4)
04

Vertical shift rule

For a vertical translation, the change is appended outside the function. Moving down by 3 units is represented by subtracting 3, giving the terminal term −3-3 in the transformed equation.

down 3:f(x)→f(x)−3\text{down }3:\quad f(x)\to f(x)-3
05

Worked Example A

Starting from y=f(x)y=f(x), the graph is translated 4 units left and 3 units down. Applying the inside-argument rule and then the outside-function rule produces the final equation y=f(x+4)−3y=f(x+4)-3, which is boxed on the board.

y=f(x+4)−3y=f(x+4)-3
06

Common misconception

Students often associate “left” with a negative number and therefore expect a minus sign. The speaker explicitly corrects this by showing that a leftward horizontal shift uses addition inside the function argument.

07

Unfinished later prompts

Parts (B) and (C) are visible on the board as additional transformation problems involving a rightward translation and reflections across the x-axis or y-axis, but neither is solved within this clip.

08

Horizontal translation rule

Horizontal shifts are made inside the function argument. A shift left by hh units gives f(x+h)f(x+h), and a shift right by hh units gives f(x−h)f(x-h). The instructor emphasizes that the sign inside the parentheses is opposite the verbal direction.

f(x)↦f(x+h) (left h),f(x)↦f(x−h) (right h)f(x) \mapsto f(x+h) \text{ (left }h),\quad f(x) \mapsto f(x-h) \text{ (right }h)
09

Vertical translation rule

Vertical shifts are made outside the function. Moving up by kk units adds kk to the whole function, and moving down by kk units subtracts kk. Example (A) uses this rule to append −3-3 after f(x+4)f(x+4).

f(x)↦f(x)+k (up k),f(x)↦f(x)−k (down k)f(x) \mapsto f(x)+k \text{ (up }k),\quad f(x) \mapsto f(x)-k \text{ (down }k)
10

Reflection across the x-axis

Reflecting across the x-axis changes the sign of every output value. Algebraically, the negative sign is placed in front of the entire function. The orange sketch illustrates a curve above the axis flipping to below it.

f(x)↦−f(x)f(x) \mapsto -f(x)
11

Reflection across the y-axis

Reflecting across the y-axis changes the sign of the input variable only. The negative sign is placed on xx inside the argument, not in front of the whole function. In the worked example, f(x−5)f(x-5) becomes f(−x−5)f(-x-5).

f(x)↦f(−x)f(x) \mapsto f(-x)
12

Worked example (A)

Starting from y=f(x)y=f(x), translate 4 units left and 3 units down. The left shift gives f(x+4)f(x+4), and the downward shift appends −3-3 outside the function.

y=f(x+4)−3y=f(x+4)-3
13

Worked example (B)

Starting from y=f(x)y=f(x), translate 5 units right and reflect across the x-axis. The right shift gives f(x−5)f(x-5), and the x-axis reflection places a negative sign in front of the whole function.

y=−f(x−5)y=-f(x-5)
14

Worked example (C)

Starting from y=f(x)y=f(x), translate 5 units right and reflect across the y-axis. The right shift gives f(x−5)f(x-5), and the y-axis reflection changes only xx to −x-x inside the argument.

y=f(−x−5)y=f(-x-5)
15

Common mistake: sign inside parentheses

A frequent error is to write x+5x+5 for a rightward shift. The clip explicitly warns that horizontal movement uses the opposite sign inside the parentheses: right means x−5x-5, left means x+4x+4 in the examples shown.

16

Common mistake: where the negative goes in reflections

The clip distinguishes two reflection rules by placement of the negative sign. For the x-axis, the negative is outside the function as in −f(x−5)-f(x-5). For the y-axis, the negative is on the input variable as in f(−x−5)f(-x-5).

Detailed learning notes

Explore conditions, steps and evidence. Supplementary explanations are labeled separately from content shown in the video.

Symbols · 14

y

Clear evidence
Shown in the video
Evidence
  1. Formula
    Observation

    The handwritten notation uses y=y= at the start of the parent-function example and again in the worked transformation equation.

  2. Audio
    Observation

    The speaker says “whether that’s written as y equals or f of x,” linking yy to the dependent-variable notation.

Symbol

y

Meaning

Dependent variable or output value of a function.

Domain

Real-valued outputs are implied by the graphing context; no explicit domain is stated.

f(x)f(x)

Clear evidence
Shown in the video
Evidence
  1. Formula
    Observation

    The board shows f(x)f(x) beside the parent-function example and inside the transformed equation y=f(x+4)−3y=f(x+4)-3.

  2. Audio
    Observation

    The speaker refers to “f of x” as an alternative way to write the function.

Symbol

f(x)f(x)

Meaning

Function notation for the value of the function ff at input xx; here used first as the parent function and then as the base expression being transformed.

x

Clear evidence
Shown in the video
Evidence
  1. Formula
    Observation

    The parent-function example is written as x2x^2, and the horizontal shift is inserted into f(x+4)f(x+4).

  2. Audio
    Observation

    The speaker discusses moving left/right relative to the input position and writes the shift inside the parentheses with xx.

Symbol

x

Meaning

Independent variable or input value of the function.

x2x^2

Clear evidence
Shown in the video
Evidence
  1. Formula
    Observation

    The board shows y=f(x)=x2y=f(x)=x^2 as the example parent function.

  2. Audio
    Observation

    The speaker says “let’s imagine we had something like x squared” and calls it the simplest version.

Symbol

x2x^2

Meaning

Quadratic parent-function rule used as the concrete example of a parent function.

+4

Clear evidence
Shown in the video
Evidence
  1. Formula
    Observation

    The worked equation becomes y=f(x+4)−3y=f(x+4)-3 after the speaker explains the left shift.

  2. Audio
    Observation

    The speaker says “if I want to move it left, I use plus.”

Symbol

+4

Meaning

Horizontal-shift term inserted inside the function argument to represent a translation 4 units left.

-3

Clear evidence
Shown in the video
Evidence
  1. Formula
    Observation

    The final boxed equation is y=f(x+4)−3y=f(x+4)-3.

  2. Audio
    Observation

    The speaker says “three down is just minus three.”

Symbol

-3

Meaning

Vertical-shift term appended outside the function to represent a translation 3 units down.

y=f(x)y = f(x)

Clear evidence
Shown in the video
Evidence
  1. Formula
    Observation

    The board repeatedly shows the base relation written as y=f(x)y = f(x).

Symbol

y=f(x)y = f(x)

Meaning

The original function relation before applying the listed transformations.

Domain

General function notation; no explicit domain is stated in the clip.

x

Clear evidence
Shown in the video
Evidence
  1. Formula
    Observation

    The variable x appears inside the transformed expressions such as f(x+4)f(x+4), f(x−5)f(x-5), and f(−x−5)f(-x-5).

  2. Audio
    Observation

    The instructor says horizontal movement goes inside the parentheses and uses x with a number.

Symbol

x

Meaning

The input variable of the function, modified for horizontal translations and reflection across the y-axis.

Domain

Input variable in the function argument.

f

Clear evidence
Shown in the video
Evidence
  1. Formula
    Observation

    The function name f is used throughout the worked examples.

Symbol

f

Meaning

The given function being transformed.

Domain

Unspecified general function.

4

Clear evidence
Shown in the video
Evidence
  1. Formula
    Observation

    Part (A) text includes translate 4 units left, and the worked formula contains x+4x+4.

  2. Audio
    Observation

    The instructor refers to moving left and using the opposite sign inside the parentheses.

Symbol

4

Meaning

The horizontal shift amount in part (A).

Domain

Positive constant used in a translation.

3

Clear evidence
Shown in the video
Evidence
  1. Formula
    Observation

    Part (A) text includes 3 down, and the worked formula ends with -3.

  2. Audio
    Observation

    The instructor discusses up/down adjustments as outside-the-function changes.

Symbol

3

Meaning

The vertical shift amount in part (A).

Domain

Positive constant used in a vertical translation.

5

Clear evidence
Shown in the video
Evidence
  1. Formula
    Observation

    Parts (B) and (C) both include translate 5 units right, and the worked formulas contain x-5.

  2. Audio
    Observation

    The instructor says five units to the right and then uses the opposite sign inside the parentheses.

Symbol

5

Meaning

The horizontal shift amount in parts (B) and (C).

Domain

Positive constant used in a translation.

Knowledge points · 8

Parent function

Clear evidence
Shown in the video
Evidence
  1. Audio
    Observation

    The speaker says, “most functions will have what is called a parent function,” and defines it as “the simplest form of a function.”

  2. Formula
    Observation

    The board writes y=f(x)=x2y=f(x)=x^2 as the example.

  3. Diagram
    Observation

    A simple upward-opening parabola is sketched next to the formula.

Definition
Explanation

A parent function is the simplest representative form of a family of functions. In this clip, the quadratic parent function is illustrated by y=f(x)=x2y=f(x)=x^2, whose basic graph is a parabola.

Formula
y=f(x)=x2y=f(x)=x^2
Conditions
  1. Used as the starting function before transformations are applied.

  2. The example shown is quadratic, but the spoken definition is general.

Types of function transformations introduced

Clear evidence
Shown in the video
Evidence
  1. Audio
    Observation

    The speaker lists possible changes: shift left/right, up/down, reflect across the x- or y-axis, stretch vertically, or compress vertically.

  2. Formula
    Observation

    The board text reads “Transformations = Shifts left, right, up, down / reflections / Vertical stretches + Compressions.”

Definition
Explanation

The clip introduces transformations as operations applied to a parent function’s graph. The named categories are translations (left, right, up, down), reflections, and vertical stretches or compressions.

Formula
Conditions
  1. These are presented as general ways to modify the graph of a parent function.

  2. Only horizontal and vertical translations are actually solved within this clip.

Prerequisites
  1. Parent function

Horizontal translation rule inside the function argument

Clear evidence
Shown in the video
Evidence
  1. Audio
    Observation

    The speaker explicitly warns that moving left is not represented by a negative sign outside the function; instead, “if I want to move it left, I use plus.”

  2. Formula
    Observation

    The worked equation inserts the shift inside the argument as f(x+4)f(x+4).

Method
Explanation

For a horizontal translation, the shift amount is placed inside the function argument with xx. In this clip, translating 4 units left is encoded as x+4x+4, so the transformed expression begins as f(x+4)f(x+4).

Formula
left 4:f(x)→f(x+4)\text{left }4:\quad f(x)\to f(x+4)
Conditions
  1. Applies to horizontal shifts of the graph of y=f(x)y=f(x).

  2. The clip demonstrates only the left-shift case explicitly.

Prerequisites
  1. Parent function
  2. Types of function transformations introduced

Vertical translation rule outside the function

Clear evidence
Shown in the video
Evidence
  1. Audio
    Observation

    The speaker says “three down is just minus three.”

  2. Formula
    Observation

    The final equation appends −3-3 outside the function: y=f(x+4)−3y=f(x+4)-3.

Method
Explanation

For a vertical translation, the shift amount is added or subtracted outside the function. In this clip, moving 3 units down is represented by appending −3-3, giving f(x+4)−3f(x+4)-3.

Formula
down 3:f(x)→f(x)−3\text{down }3:\quad f(x)\to f(x)-3
Conditions
  1. Applies to vertical shifts of the graph of y=f(x)y=f(x).

  2. The clip demonstrates the downward case explicitly.

Prerequisites
  1. Parent function
  2. Types of function transformations introduced

Horizontal translation rule for f(x)f(x)

Clear evidence
Shown in the video
Evidence
  1. Audio
    Observation

    The instructor explains that when moving left or right, the change goes inside the parentheses and the plus or minus is opposite of what you would expect.

  2. Formula
    Observation

    Translate 4 units left is written as f(x+4)f(x+4); translate 5 units right is written as f(x−5)f(x-5).

Method
Explanation

For a horizontal shift, modify the input variable inside the function argument. A shift to the left by h units corresponds to replacing x by x+hx+h, while a shift to the right by h units corresponds to replacing x by x-h. The instructor emphasizes that the sign inside the parentheses is opposite the intuitive direction word.

Formula
f(x)↦f(x+h) for left h,f(x)↦f(x−h) for right hf(x) \mapsto f(x+h) \text{ for left } h,\quad f(x) \mapsto f(x-h) \text{ for right } h
Conditions
  1. The transformation is applied to the input variable x.

  2. The shift amount is a positive constant h.

Prerequisites
  1. y=f(x)y = f(x)
  2. x

Vertical translation rule for f(x)f(x)

Clear evidence
Shown in the video
Evidence
  1. Audio
    Observation

    The instructor contrasts horizontal changes with up/down changes and treats vertical shifts as easier adjustments outside the function.

  2. Formula
    Observation

    Part (A) shows 3 down as an appended -3 outside the function: f(x+4)−3f(x+4)-3.

Method
Explanation

For a vertical shift, add or subtract a constant outside the function. Moving down by k units subtracts k from the whole function value, while moving up by k units adds k. In the worked example, 3 down is represented by appending -3 after f(x+4)f(x+4).

Formula
f(x)↦f(x)+k for up k,f(x)↦f(x)−k for down kf(x) \mapsto f(x)+k \text{ for up } k,\quad f(x) \mapsto f(x)-k \text{ for down } k
Conditions
  1. The transformation is applied after evaluating the function.

  2. The shift amount is a positive constant k.

Prerequisites
  1. y=f(x)y = f(x)

Reflection across the x-axis

Clear evidence
Shown in the video
Evidence
  1. Audio
    Observation

    The instructor says that if you are reflecting across the x-axis, something on top flips over to the bottom, so you put a negative sign in front of the entire function.

  2. Formula
    Observation

    Part (B) changes from f(x−5)f(x-5) to -f(x-5).

  3. Diagram
    Observation

    An orange sketch shows a curve above a horizontal line flipping to below it.

Definition
Explanation

Reflecting a graph across the x-axis changes the sign of every output value. Algebraically, this is done by placing a negative sign in front of the entire function, not inside the argument. The instructor visually describes this as the top of the graph flipping over to the bottom.

Formula
f(x)↦−f(x)f(x) \mapsto -f(x)
Conditions
  1. The reflection is across the x-axis.

  2. The negative sign applies to the whole function value.

Prerequisites
  1. y=f(x)y = f(x)
  2. -f(⋯\cdots)

Reflection across the y-axis

Clear evidence
Shown in the video
Evidence
  1. Audio
    Observation

    The instructor says that when reflecting across the y-axis, you only make the x negative.

  2. Formula
    Observation

    Part (C) changes from f(x−5)f(x-5) to f(−x−5)f(-x-5).

Definition
Explanation

Reflecting a graph across the y-axis changes the sign of the input variable only. Algebraically, this means replacing x by -x inside the function argument while leaving the outside of the function unchanged. In the worked example, the translated expression f(x−5)f(x-5) becomes f(−x−5)f(-x-5).

Formula
f(x)↦f(−x)f(x) \mapsto f(-x)
Conditions
  1. The reflection is across the y-axis.

  2. The negative sign is applied only to the input variable x.

Prerequisites
  1. y=f(x)y = f(x)
  2. x
  3. -x
Claims and conditions · 5

Leftward horizontal translation uses addition inside the argument

Clear evidence
Shown in the video
Evidence
  1. Audio
    Observation

    The speaker states that when moving left, one should use plus rather than minus, calling this the key point that causes issues.

  2. Formula
    Observation

    The worked solution writes f(x+4)f(x+4) for a translation 4 units left.

Proposition
Statement

To translate the graph of y=f(x)y=f(x) four units left, replace xx by x+4x+4, producing y=f(x+4)y=f(x+4).

Hypotheses
  1. The starting graph has equation y=f(x)y=f(x).

  2. The intended transformation is a horizontal translation 4 units left.

Quantifiers

For the specific example shown in the clip.

Downward vertical translation uses subtraction outside the function

Clear evidence
Shown in the video
Evidence
  1. Audio
    Observation

    The speaker says “three down is just minus three.”

  2. Formula
    Observation

    The final boxed equation is y=f(x+4)−3y=f(x+4)-3.

Proposition
Statement

To translate the graph of y=f(x)y=f(x) three units down, append −3-3 to the function, producing y=f(x)−3y=f(x)-3; combined with the left shift, the result is y=f(x+4)−3y=f(x+4)-3.

Hypotheses
  1. The starting graph has equation y=f(x)y=f(x).

  2. The intended transformation includes a vertical translation 3 units down.

Quantifiers

For the specific example shown in the clip.

Horizontal shifts use the opposite sign inside the argument

Clear evidence
Shown in the video
Evidence
  1. Audio
    Observation

    The instructor states that for left/right movement, the plus or minus inside the parentheses is opposite of what you would expect.

  2. Formula
    Observation

    Left 4 becomes x+4x+4, and right 5 becomes x-5 in the worked examples.

Proposition
Statement

When translating a function horizontally, the sign inserted with x inside the parentheses is opposite the verbal direction: left uses + and right uses -.

Hypotheses
  1. The transformation is a horizontal translation of f(x)f(x).

  2. The shift amount is positive.

Quantifiers

For the horizontal translations demonstrated in this clip.

Reflection across the x-axis places the negative sign outside the function

Clear evidence
Shown in the video
Evidence
  1. Audio
    Observation

    The instructor says that reflecting across the x-axis means putting a negative sign in front of the entire function.

  2. Formula
    Observation

    The worked result for part (B) is -f(x-5).

Proposition
Statement

To reflect a graph across the x-axis, multiply the entire function by -1.

Hypotheses
  1. The reflection is across the x-axis.

Quantifiers

For the function-transformation setting shown in the clip.

Reflection across the y-axis places the negative sign on x

Clear evidence
Shown in the video
Evidence
  1. Audio
    Observation

    The instructor says that when reflecting across the y-axis, you only make the x negative.

  2. Formula
    Observation

    The worked result for part (C) is f(−x−5)f(-x-5).

Proposition
Statement

To reflect a graph across the y-axis, replace x by -x inside the function argument.

Hypotheses
  1. The reflection is across the y-axis.

Quantifiers

For the function-transformation setting shown in the clip.

Derivations and proofs · 3

Derivation of the equation for Example A

Clear evidence
Shown in the video
Evidence
  1. Audio
    Observation

    The speaker builds the answer step by step from the base idea y=f(x)y=f(x), first handling the left shift and then the down shift.

  2. Formula
    Observation

    The board shows the progression from y=f(x)y=f(x) to y=f(x+4)−3y=f(x+4)-3.

Proof
Steps
  1. Expression
    y=f(x)y=f(x)
    Explanation

    Start from the given parent-form equation for the untransformed graph.

    Justification

    This is the base function specified in the problem statement on the board.

    Shown in the video
  2. Expression
    y=f(x+4)y=f(x+4)
    Explanation

    Apply the horizontal translation 4 units left by inserting +4+4 inside the function argument.

    Justification

    The speaker explicitly states that moving left uses plus inside the parentheses.

    Shown in the video
  3. Expression
    y=f(x+4)−3y=f(x+4)-3
    Explanation

    Apply the vertical translation 3 units down by subtracting 3 outside the function.

    Justification

    The speaker states that “three down is just minus three.”

    Shown in the video
Conclusion

The transformed equation for translating y=f(x)y=f(x) four units left and three units down is y=f(x+4)−3y=f(x+4)-3.

Derivation of the formula for part (B)

Clear evidence
Shown in the video
Evidence
  1. Formula
    Observation

    The board shows the prompt translate 5 units right, reflect across the x-axis, and the worked answer develops into -f(x-5).

  2. Audio
    Observation

    The instructor narrates the right shift first and then the x-axis reflection.

Proof
Steps
  1. Expression
    y=f(x)y=f(x)
    Explanation

    Start from the original function relation shown on the board.

    Justification

    Base function given in the problem setup.

    Shown in the video
  2. Expression
    f(x−5)f(x-5)
    Explanation

    Apply the horizontal translation 5 units to the right by subtracting 5 from x inside the argument.

    Justification

    Horizontal translation rule: right by h gives x-h.

    Shown in the video
  3. Expression
    −f(x−5)-f(x-5)
    Explanation

    Apply the reflection across the x-axis by placing a negative sign in front of the whole function.

    Justification

    Reflection across the x-axis changes the sign of the output values.

    Shown in the video
Conclusion

The transformed equation for part (B) is y=−f(x−5)y=-f(x-5).

Derivation of the formula for part (C)

Clear evidence
Shown in the video
Evidence
  1. Formula
    Observation

    The board shows the prompt translate 5 units right, reflect across the y-axis, and the worked answer develops into f(−x−5)f(-x-5).

  2. Audio
    Observation

    The instructor repeats the right-shift step and then says to make only the x negative for the y-axis reflection.

Proof
Steps
  1. Expression
    y=f(x)y=f(x)
    Explanation

    Start again from the original function relation.

    Justification

    Base function given in the problem setup.

    Shown in the video
  2. Expression
    f(x−5)f(x-5)
    Explanation

    Apply the horizontal translation 5 units to the right.

    Justification

    Horizontal translation rule: right by h gives x-h.

    Shown in the video
  3. Expression
    f(−x−5)f(-x-5)
    Explanation

    Apply the reflection across the y-axis by changing only the x term to -x inside the argument.

    Justification

    Reflection across the y-axis replaces x by -x.

    Shown in the video
Conclusion

The transformed equation for part (C) is y=f(−x−5)y=f(-x-5).

Worked examples · 6

Example A: translate 4 units left, 3 down

Clear evidence
Shown in the video
Evidence
  1. Caption evidence
    Observation

    The board text reads “(Ex) Write the equation for the transformation of the graph y=f(x)y=f(x)” and “(A) translate 4 units left, 3 down.”

  2. Audio
    Observation

    The speaker reads the prompt aloud and solves part A.

  3. Formula
    Observation

    The final handwritten answer is boxed as y=f(x+4)−3y=f(x+4)-3.

Problem

Write the equation for the transformation of the graph y=f(x)y=f(x) when it is translated 4 units left and 3 units down.

Given
  1. Original graph: y=f(x)y=f(x).

  2. Transformation: 4 units left.

  3. Transformation: 3 units down.

Goal

Find the equation of the transformed graph.

Steps
  1. Expression
    y=f(x)y=f(x)
    Explanation

    Begin with the original function notation given in the problem.

    Justification

    This is the starting equation stated on the board.

    Shown in the video
  2. Expression
    y=f(x+4)y=f(x+4)
    Explanation

    Encode the leftward horizontal shift by adding 4 inside the argument.

    Justification

    The speaker identifies this as the key rule: left means plus inside f(⋅)f(\cdot).

    Shown in the video
  3. Expression
    y=f(x+4)−3y=f(x+4)-3
    Explanation

    Encode the downward vertical shift by subtracting 3 outside the function.

    Justification

    The speaker directly states that 3 down corresponds to −3-3.

    Shown in the video
Answer

y=f(x+4)−3y=f(x+4)-3

Verification

The final equation matches the boxed handwritten result on the board.

Example B prompt: translate 5 units right, reflect across the x-axis

Clear evidence
Shown in the video
Evidence
  1. Caption evidence
    Observation

    The board shows “(B) translate 5 units right, reflect across the x-axis.”

  2. Audio
    Observation

    The speaker says “Let’s try the second one. Letter B. Translate…” but the clip ends before the solution is completed.

Uncertainties
  1. No worked steps or final equation for part B appear within the provided clip.

  2. The exact intended answer is not shown in this segment.

Problem

Write the equation for the transformation of the graph y=f(x)y=f(x) when it is translated 5 units right and reflected across the x-axis.

Given
  1. Original graph: y=f(x)y=f(x).

  2. Transformation: 5 units right.

  3. Transformation: reflect across the x-axis.

Goal

Find the equation of the transformed graph.

Steps
  1. Expression
    (prompt shown only)\text{(prompt shown only)}
    Explanation

    The problem statement is visible on the board, but no solution steps are completed in this clip.

    Justification

    The video reaches the end of the segment while introducing part B.

    Shown in the video
Answer

Not completed within this clip.

Verification

Only the prompt is present; no final answer is displayed before the clip ends.

Example C prompt: translate 5 units right, reflect across the y-axis

Clear evidence
Shown in the video
Evidence
  1. Caption evidence
    Observation

    The board shows “(C) translate 5 units right, reflect across the y-axis.”

  2. Audio
    Observation

    The speaker does not solve part C in this clip.

Uncertainties
  1. No worked steps or final equation for part C appear within the provided clip.

  2. The exact intended answer is not shown in this segment.

Problem

Write the equation for the transformation of the graph y=f(x)y=f(x) when it is translated 5 units right and reflected across the y-axis.

Given
  1. Original graph: y=f(x)y=f(x).

  2. Transformation: 5 units right.

  3. Transformation: reflect across the y-axis.

Goal

Find the equation of the transformed graph.

Steps
  1. Expression
    (prompt shown only)\text{(prompt shown only)}
    Explanation

    The problem statement is visible on the board, but no solution steps are completed in this clip.

    Justification

    The segment ends before part C is addressed.

    Shown in the video
Answer

Not completed within this clip.

Verification

Only the prompt is present; no final answer is displayed before the clip ends.

Example (A): translate 4 units left, 3 down

Clear evidence
Shown in the video
Evidence
  1. Formula
    Observation

    The board shows (A) translate 4 units left, 3 down and the completed answer y=f(x+4)−3y=f(x+4)-3.

  2. Audio
    Observation

    The instructor discusses left/right movement going inside the parentheses and up/down movement as an outside adjustment.

Problem

Given y=f(x)y=f(x), write the transformed equation for a translation 4 units left and 3 units down.

Given
  1. Original function: y=f(x)y=f(x)

  2. Horizontal shift: 4 units left

  3. Vertical shift: 3 units down

Goal

Produce the transformed formula.

Steps
  1. Expression
    f(x+4)f(x+4)
    Explanation

    Move 4 units left by adding 4 inside the function argument.

    Justification

    Horizontal translation rule: left by h gives x+hx+h.

    Shown in the video
  2. Expression
    f(x+4)−3f(x+4)-3
    Explanation

    Move 3 units down by subtracting 3 outside the function.

    Justification

    Vertical translation rule: down by k gives -k outside the function.

    Shown in the video
Answer

y=f(x+4)−3y=f(x+4)-3

Verification

The final boxed expression on the board matches the stated transformations.

Example (B): translate 5 units right, reflect across the x-axis

Clear evidence
Shown in the video
Evidence
  1. Formula
    Observation

    The board shows (B) translate 5 units right, reflect across the x-axis and the completed answer y=−f(x−5)y=-f(x-5).

  2. Audio
    Observation

    The instructor explicitly says to go opposite for the right shift and then put a negative sign in front of the entire function for the x-axis reflection.

Problem

Given y=f(x)y=f(x), write the transformed equation after translating 5 units right and reflecting across the x-axis.

Given
  1. Original function: y=f(x)y=f(x)

  2. Horizontal shift: 5 units right

  3. Reflection: across the x-axis

Goal

Produce the transformed formula.

Steps
  1. Expression
    f(x−5)f(x-5)
    Explanation

    Translate 5 units right by subtracting 5 from x inside the argument.

    Justification

    Horizontal translation rule: right by h gives x-h.

    Shown in the video
  2. Expression
    −f(x−5)-f(x-5)
    Explanation

    Reflect across the x-axis by multiplying the whole function by -1.

    Justification

    Reflection across the x-axis changes the sign of all outputs.

    Shown in the video
Answer

y=−f(x−5)y=-f(x-5)

Verification

The final boxed expression on the board is -f(x-5).

Example (C): translate 5 units right, reflect across the y-axis

Clear evidence
Shown in the video
Evidence
  1. Formula
    Observation

    The board shows (C) translate 5 units right, reflect across the y-axis and the completed answer y=f(−x−5)y=f(-x-5).

  2. Audio
    Observation

    The instructor says that for the y-axis reflection, only the x becomes negative.

Problem

Given y=f(x)y=f(x), write the transformed equation after translating 5 units right and reflecting across the y-axis.

Given
  1. Original function: y=f(x)y=f(x)

  2. Horizontal shift: 5 units right

  3. Reflection: across the y-axis

Goal

Produce the transformed formula.

Steps
  1. Expression
    f(x−5)f(x-5)
    Explanation

    Translate 5 units right by subtracting 5 from x inside the argument.

    Justification

    Horizontal translation rule: right by h gives x-h.

    Shown in the video
  2. Expression
    f(−x−5)f(-x-5)
    Explanation

    Reflect across the y-axis by replacing x with -x inside the argument.

    Justification

    Reflection across the y-axis changes the sign of the input variable only.

    Shown in the video
Answer

y=f(−x−5)y=f(-x-5)

Verification

The final boxed expression on the board is f(−x−5)f(-x-5).

Visual events · 5

Opening board layout and topic outline

Clear evidence
Shown in the video
Evidence
  1. Diagram
    Observation

    The page header reads “2-6 Functions, Equations, and Graphs” and “FAMILIES OF FUNCTIONS.” Below it are handwritten notes: “Parent function” and “Transformations = Shifts left, right, up, down / reflections / Vertical stretches + Compressions.”

  2. Animation
    Observation

    The speaker writes y=f(x)=x2y=f(x)=x^2 next to “Parent function.”

Objects
  1. Title text

  2. Handwritten section heading

  3. Parent-function note

  4. Transformations list

Changes
  1. The parent-function example y=f(x)=x2y=f(x)=x^2 is added during the opening explanation.

Invariants
  1. The overall lesson topic remains families of functions and transformations.

Interpretation

The visual organization establishes that the lesson will define a parent function and then classify common transformations of its graph.

Sketch of the quadratic parent graph

Clear evidence
Shown in the video
Evidence
  1. Diagram
    Observation

    A small upward-opening parabola is drawn beside y=f(x)=x2y=f(x)=x^2.

  2. Audio
    Observation

    The speaker says the example “would be a parabola, nice and simple.”

Objects
  1. Parabola sketch

  2. Formula y=f(x)=x2y=f(x)=x^2

Changes
  1. A simple U-shaped curve is added to visualize the parent function.

Invariants
  1. The sketch represents the untransformed parent graph only.

Interpretation

The drawing links the algebraic rule x2x^2 to its standard graphical shape, a parabola.

Construction of the answer for Example A

Clear evidence
Shown in the video
Evidence
  1. Animation
    Observation

    Under part (A), the equation is built progressively until the final boxed form y=f(x+4)−3y=f(x+4)-3 appears.

  2. Diagram
    Observation

    The final answer is enclosed in a pink box.

Objects
  1. Problem text for (A)

  2. Handwritten equation

  3. Pink box around the final answer

Changes
  1. The equation develops from the base form to the fully transformed form y=f(x+4)−3y=f(x+4)-3.

Invariants
  1. The original prompt remains “translate 4 units left, 3 down.”

Interpretation

The visual writing sequence shows how each verbal transformation rule is encoded symbolically in the final equation.

Orange sketch illustrating reflection across the x-axis

Clear evidence
Shown in the video
Evidence
  1. Diagram
    Observation

    An orange horizontal line is drawn, then a curved shape above it, followed by a mirrored curved shape below it.

  2. Audio
    Observation

    The instructor says that if something is on top, it would flip over and end up on the bottom because this is the x-axis.

Objects
  1. orange horizontal line representing the x-axis

  2. upper orange curve

  3. lower orange curve

Changes
  1. A curve above the line is drawn first.

  2. A matching curve below the line is added to show the flipped position.

Invariants
  1. The horizontal line stays fixed as the mirror axis.

  2. The sketch is used to represent sign change of output values.

Interpretation

The drawing visually supports the rule that reflection across the x-axis sends positive-height portions of the graph to negative-height portions, corresponding to multiplying the whole function by -1.

Color-coded organization of the worked transformations

Clear evidence
Shown in the video
Evidence
  1. Diagram
    Observation

    Different parts of the board use blue, pink/magenta, orange, and green ink for prompts, intermediate terms, and final boxed answers.

  2. Audio
    Observation

    The instructor mentions switching colors when discussing different transformation pieces.

Uncertainties
  1. Exact color assignment varies across moments and is not fully labeled on screen.

Objects
  1. blue handwritten formulas

  2. pink/magenta emphasis on vertical-shift discussion

  3. orange emphasis for x-axis reflection work

  4. green emphasis for y-axis reflection work

Changes
  1. The board accumulates three worked examples from top to bottom.

  2. Final answers are boxed in colored outlines.

Invariants
  1. The original prompts remain visible while the solutions are built underneath them.

Interpretation

The color coding helps separate horizontal-shift ideas, vertical-shift ideas, and the two different reflection rules.

Misconceptions · 3

Confusing a leftward shift with a minus sign

Clear evidence
Shown in the video
Evidence
  1. Audio
    Observation

    The speaker says that when thinking of moving left from the origin, one naturally thinks of negative 4, “but that’s not what this is,” and then emphasizes that left uses plus inside the function.

Misconception

Because moving left on a number line corresponds to negative values, students may expect a left translation to be written with a minus sign.

Clarification

For horizontal translations of y=f(x)y=f(x), a shift left is represented by adding inside the argument, as in f(x+4)f(x+4), not by subtracting there.

Assuming right means + inside the parentheses

Clear evidence
Shown in the video
Evidence
  1. Audio
    Observation

    The instructor explicitly warns that when thinking of right, one may think plus, but the needed sign is the opposite.

Misconception

Learners may expect a rightward horizontal translation to be written with +x.

Clarification

The clip states that horizontal movement goes inside the parentheses and the sign is opposite the intuitive direction: right uses x-h, left uses x+hx+h.

Putting the negative sign in the wrong place for reflections

Clear evidence
Shown in the video
Evidence
  1. Audio
    Observation

    The instructor distinguishes x-axis reflection from y-axis reflection by where the negative sign is placed.

  2. Formula
    Observation

    Part (B) uses -f(x-5), while part (C) uses f(−x−5)f(-x-5).

Misconception

Learners may confuse which reflection requires a negative outside the function and which requires a negative on x inside the function.

Clarification

Reflection across the x-axis puts the negative in front of the entire function, while reflection across the y-axis puts the negative only on x inside the argument.

Concept relations · 11

Parent function → Types of function transformations introduced

Clear evidence
Shown in the video
Evidence
  1. Audio
    Observation

    The speaker first defines the parent function and then immediately lists transformations that can be applied to it.

  2. Diagram
    Observation

    The board places “Parent function” above the list of transformation types.

Prerequisite
Explanation

The notion of a parent function is needed before discussing transformations, because transformations are described as changes made to the graph of that simplest base function.

Types of function transformations introduced → Horizontal translation rule inside the function argument

Clear evidence
Shown in the video
Evidence
  1. Audio
    Observation

    After listing transformations generally, the speaker narrows to the specific rule for horizontal shifts in Example A.

  2. Formula
    Observation

    The general category “Shifts left, right” becomes the concrete expression f(x+4)f(x+4) in the worked example.

Contains
Explanation

The broad category of transformations includes horizontal translations, and the clip then specifies the rule for encoding a leftward shift inside the function argument.

Types of function transformations introduced → Vertical translation rule outside the function

Clear evidence
Shown in the video
Evidence
  1. Audio
    Observation

    The general list includes up/down shifts, and the worked example applies the down-shift rule explicitly.

  2. Formula
    Observation

    The general category becomes the concrete appended term −3-3 in f(x+4)−3f(x+4)-3.

Contains
Explanation

Vertical translations are one member of the transformation family introduced earlier, and the clip demonstrates the downward case by appending −3-3 outside the function.

Horizontal translation rule inside the function argument → Example A: translate 4 units left, 3 down

Clear evidence
Shown in the video
Evidence
  1. Formula
    Observation

    Example A uses the rule directly by writing f(x+4)f(x+4) for a left shift.

Application
Explanation

Example A applies the horizontal-shift rule to turn the verbal instruction “4 units left” into the symbolic term x+4x+4 inside the function.

Vertical translation rule outside the function → Example A: translate 4 units left, 3 down

Clear evidence
Shown in the video
Evidence
  1. Formula
    Observation

    Example A uses the rule directly by appending −3-3 for a downward shift.

Application
Explanation

Example A applies the vertical-shift rule to turn the verbal instruction “3 down” into the symbolic term −3-3 outside the function.

Horizontal translation rule for f(x)f(x) → Vertical translation rule for f(x)f(x)

Clear evidence
Shown in the video
Evidence
  1. Audio
    Observation

    The instructor contrasts inside-the-parentheses changes for left/right with outside changes for up/down.

  2. Formula
    Observation

    Part (A) combines f(x+4)f(x+4) with -3 outside.

Contrast
Explanation

Horizontal translations modify the input inside f( ), while vertical translations modify the output outside f( ).

Reflection across the x-axis → Reflection across the y-axis

Clear evidence
Shown in the video
Evidence
  1. Formula
    Observation

    The worked examples compare -f(x-5) and f(−x−5)f(-x-5).

  2. Audio
    Observation

    The instructor explicitly says these are almost exactly the same except for where the negative sign goes.

Contrast
Explanation

Both are reflections, but the x-axis reflection negates the whole function value, whereas the y-axis reflection negates only the input variable.

Example (B): translate 5 units right, reflect across the x-axis → Horizontal translation rule for f(x)f(x)

Clear evidence
Shown in the video
Evidence
  1. Formula
    Observation

    Part (B) is built from a right shift followed by an x-axis reflection.

Application
Explanation

Example (B) applies the horizontal translation rule to obtain f(x−5)f(x-5).

Example (B): translate 5 units right, reflect across the x-axis → Reflection across the x-axis

Clear evidence
Shown in the video
Evidence
  1. Formula
    Observation

    Part (B) ends as -f(x-5).

Application
Explanation

Example (B) applies the x-axis reflection rule by placing a negative sign in front of the whole function.

Example (C): translate 5 units right, reflect across the y-axis → Horizontal translation rule for f(x)f(x)

Clear evidence
Shown in the video
Evidence
  1. Formula
    Observation

    Part (C) is built from a right shift followed by a y-axis reflection.

Application
Explanation

Example (C) applies the horizontal translation rule to obtain f(x−5)f(x-5).

Example (C): translate 5 units right, reflect across the y-axis → Reflection across the y-axis

Clear evidence
Shown in the video
Evidence
  1. Formula
    Observation

    Part (C) ends as f(−x−5)f(-x-5).

Application
Explanation

Example (C) applies the y-axis reflection rule by changing x to -x inside the argument.

Find an answer · 10

What is a parent function in this lesson?

Clear evidence
Shown in the video
Evidence
  1. Audio
    Observation

    The speaker defines parent function and gives x2x^2 as the example.

Knowledge points
  1. Parent function

What kinds of function transformations are introduced?

Clear evidence
Shown in the video
Evidence
  1. Formula
    Observation

    The board lists shifts, reflections, and vertical stretches/compressions.

Knowledge points
  1. Types of function transformations introduced

Why does moving left use plus inside the function argument?

Clear evidence
Shown in the video
Evidence
  1. Audio
    Observation

    The speaker explicitly contrasts the intuitive “negative 4” idea with the actual rule of using plus for a left shift.

Knowledge points
  1. Horizontal translation rule inside the function argument
  2. Confusing a leftward shift with a minus sign

How do you write the equation for translating y=f(x)y=f(x) 4 units left and 3 units down?

Clear evidence
Shown in the video
Evidence
  1. Formula
    Observation

    The worked answer for part A is shown as y=f(x+4)−3y=f(x+4)-3.

Knowledge points
  1. Example A: translate 4 units left, 3 down
  2. Horizontal translation rule inside the function argument
  3. Vertical translation rule outside the function

Are examples B and C actually solved in this clip?

Clear evidence
Shown in the video
Evidence
  1. Caption evidence
    Observation

    Parts B and C are visible as prompts, but the clip ends before their solutions are written.

Knowledge points
  1. Example B prompt: translate 5 units right, reflect across the x-axis
  2. Example C prompt: translate 5 units right, reflect across the y-axis

Why does translating right use x-5 instead of x+5x+5?

Clear evidence
Shown in the video
Evidence
  1. Audio
    Observation

    The instructor repeatedly says the sign inside the parentheses is opposite the direction word.

Knowledge points
  1. Horizontal translation rule for f(x)f(x)
  2. Horizontal shifts use the opposite sign inside the argument
  3. Example (B): translate 5 units right, reflect across the x-axis
  4. Example (C): translate 5 units right, reflect across the y-axis

Where does the negative sign go when reflecting across the x-axis?

Clear evidence
Shown in the video
Evidence
  1. Audio
    Observation

    The instructor explains the top-to-bottom flip and places the negative in front of the whole function.

Knowledge points
  1. Reflection across the x-axis
  2. Reflection across the x-axis places the negative sign outside the function
  3. Example (B): translate 5 units right, reflect across the x-axis

How is reflection across the y-axis written algebraically?

Clear evidence
Shown in the video
Evidence
  1. Audio
    Observation

    The instructor says only the x becomes negative for reflection across the y-axis.

Knowledge points
  1. Reflection across the y-axis
  2. Reflection across the y-axis places the negative sign on x
  3. Example (C): translate 5 units right, reflect across the y-axis

How do you combine a horizontal shift with a vertical shift or a reflection?

Clear evidence
Shown in the video
Evidence
  1. Formula
    Observation

    The board shows combined transformations such as f(x+4)−3f(x+4)-3, -f(x-5), and f(−x−5)f(-x-5).

Knowledge points
  1. Example (A): translate 4 units left, 3 down
  2. Example (B): translate 5 units right, reflect across the x-axis
  3. Example (C): translate 5 units right, reflect across the y-axis
  4. Horizontal translation rule for f(x)f(x)
  5. Vertical translation rule for f(x)f(x)

What is the difference between -f(x-5) and f(−x−5)f(-x-5)?

Clear evidence
Shown in the video
Evidence
  1. Audio
    Observation

    The instructor notes that the last two problems are almost exactly the same except for the reflection type.

  2. Formula
    Observation

    The final answers differ as -f(x-5) versus f(−x−5)f(-x-5).

Knowledge points
  1. Reflection across the x-axis
  2. Reflection across the y-axis
  3. Example (B): translate 5 units right, reflect across the x-axis
  4. Example (C): translate 5 units right, reflect across the y-axis
Coverage and review notes

Covered · Opening title and spoken introduction to the topic of families of functions.

Covered · Definition of parent function with the example y=f(x)=x2y=f(x)=x^2 and a parabola sketch.

Covered · Overview of transformation types: shifts, reflections, vertical stretches and compressions.

Covered · Transition to worked examples; the speaker notes that three examples will be used and that one point will cause issues.

Covered · Reading of Example A and setup of the common misconception about leftward movement.

Covered · Step-by-step derivation of y=f(x+4)−3y=f(x+4)-3 for Example A; prompts for Examples B and C are visible but not solved before the clip ends.

Covered · The board shows parts (A), (B), and (C); the instructor begins part (B) by writing the rightward horizontal translation f(x−5)f(x-5).

Covered · The instructor explains x-axis reflection, sketches the flip, and completes part (B) as -f(x-5).

Covered · The instructor works part (C), first writing f(x−5)f(x-5) and then changing it to f(−x−5)f(-x-5), followed by a spoken summary contrasting the rules.

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