Question

If $A=(a_{ij}{)}_{n\times n}$ and f is a function, we define $f\left(A\right)=\left(f\right(a_{ih}){)}_{n\times n}$.
Let $A=\left(\begin{array}{cc}\pi /2-\theta & \theta \\ -\theta & \pi /2-\theta \end{array}\right)$

• A. sin A is invertible
• B. sin A = cos A
• C. sin A is orthogonal
• D. sin (2A) = 2 sin A cos A

Answer 1

Answer: (A), (C)

The correct options are
A sin A is invertible
C sin A is orthogonal