Linear algebra eigenvalues and diagonalizable matrix Let $A$ be an $n\times n$ matrix over $\mathbb{C}$.
First I don't understand why $AA^*$ can be diagnosable over $\mathbb{C}$.
And why $i+1$ can't be eigenvalue of $AA^*$?
Hope question is clear enough and I don't have any spelling mistake and used right expressions.

$\textbf{Hint:}$ Any hermitian matrix is diagonalizable. Prove, by definition, that $AA^*$ is a hermitian.
