When applying the Monotone Convergence Principle to the right endpoints , what specific properties must the sequence satisfy?
The sequence must be monotone decreasing (non-increasing) and bounded below. In the context of nested intervals, follows from the containment , ensuring monotonicity. Boundedness below is ensured because for all (since is the smallest possible left bound, and actually is not quite right, rather and is increasing, so is bounded below by any , specifically works as a loose lower bound, or more precisely, the entire sequence is trapped between and ). Actually, simpler: , so is bounded below by .
Conditions
- Intervals are nested: .
Reasoning, step by step
- Verify monotonicity: From inclusion, .
- Verify boundedness: Find a constant such that for all .
- Observe that and (since increases from ).
- Therefore, for all .
- Conclude that is decreasing and bounded below, hence convergent.
Example
Script states: 'the sequence of right endpoints is strictly decreasing and has a lower bound.'
Common misconceptions
- Thinking needs to be bounded above (it is naturally bounded by ).
- Confusing the direction of monotonicity for right vs left endpoints.
Watch the explanation
BilibiliThe nested interval theorem
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