$A^2=A^*A$. Why is matrix $A$ Hermitian?
36090
$TT^*=T^2$, show that $T$ is self-adjoint
109736
For a 2x2 matrix A satisfying $A^k=I$, compute $e^A$
152102
Prove that for every complex $2$x$2$ matrix $A$, there exists a matrix $X$ such that $X^3=A^2$.
158082
Is $\|A^n\|=\|A\|^n$ true for any normal operator in a Hilbert space?
145980
For every matrix $A\in M_{2}( \mathbb{C}) $ there's  $X\in M_{2}( \mathbb{C})$ such that $X^2=A$?
10828
If $A^2 = I$, then $A$ is diagonalizable, and is $I$ if $1$ is its only eigenvalue
54118
Proving Eigenvalue squared is Eigenvalue of $A^2$
78755
If matrix $A$ is unitary and $B^2=A$, is $B$ necessarily unitary?
100656
$2\times2$ matrix $A$ such that $A$ has one independent eigenvector while $A^{2}$ has two independent eigenvectors
83936
Why is the Dirac mass term Hermitian if Grassmann-valued fields anticommute?
116539
Eigenvalues of matrix satisfying $A^2 = A$
131701
Why is $A^TA$ invertible if $A$ has independent columns?
151806
Prove that $A^k = 0 $ iff $A^2 = 0$
3150
Is there an intuitive interpretation of $A^TA$ for a data matrix $A$?
88349
Are the eigenvalues of $AB$ equal to the eigenvalues of $BA$? (Citation needed!)
93835
Why do those terms vanish if the metric is Hermitian?
131844
When does $(e^a)^b = e^{ab}$ hold?