Understand why↗
A 90-degree rotation moves every non-zero vector in the plane off its original line (span). Since eigenvectors must remain on their span, no real vector qualifies.
Conditions: Matrix represents a pure 90-degree rotation in 2D; Searching for real-valued eigenvectors
A 90-degree rotation moves every non-zero vector in the plane off its original line (span). Since eigenvectors must remain on their span, no real vector qualifies.
Conditions: Matrix represents a pure 90-degree rotation in 2D; Searching for real-valued eigenvectors