Let $A$ be the $2\times 2$ matrix representing the reflection in the line $y=2x$. Are the eigenvalues of $A$
(a) $\lambda_1=1$, $\lambda_2=0$
(b) $\lambda_1=-1$, $\lambda_2=0$
(c) $\lambda_1=1$, $\lambda_2=-1$
(d) None of the above?
Hello, I know how to calculate Eigen values when giving a matrix, but I'm not sure what this question means exactly. Any help is greatly appreciated