Is $A^2-A=A(A-I)$ in matrices?
42141
Proving Distributivity of Matrix Multiplication
118417
Is $AA^T$ positive semidefinite?
24809
For all square matrices $A$ and $B$ of the same size, it is true that $(A+B)^2 = A^2 + 2AB + B^2$?
32487
Proving $\det \left( \begin{smallmatrix} A & -B \\ B & A \end{smallmatrix} \right) =|\det(A+iB)|^2$
154327
$A^2X = X$ show that $AX = X$, if $A_{ij} > 0$ and $x_{i} > 0$
60006
Matrix equation: $A−A(A + B)^{−1}A = B−B(A + B)^{−1}B$
57731
Can commuting matrices $X,Y$ always be written as polynomials of some matrix $A$?
10828
If $A^2 = I$, then $A$ is diagonalizable, and is $I$ if $1$ is its only eigenvalue
7817
Help to compute all powers $A^{n}$ and find is the matrix of $A$ diagonal?
129564
Show that $A$ is an invertible matrix if $\left(A+I\right)^3=0$ and find $A^{-1}$
139162
Complex number isomorphic to certain $2\times 2$ matrices?
113168
If $a > b$, is $a^2 > b^2$?
34372
Are $10\times 10$ matrices spanned by powers of a single matrix?
148946
If $\mathbf{A}$ is a $2\times 2$ matrix that satisfies $\mathbf{A}^2 - 4\mathbf{A} - 7\mathbf{I} = \mathbf{0}$, then $\mathbf{A}$ is invertible
52357
If $a,b \in G$, show that $ab^{n}a^{-1}=(aba^{-1})^{n}$.
116539
Eigenvalues of matrix satisfying $A^2 = A$
145980
For every matrix $A\in M_{2}( \mathbb{C}) $ there's  $X\in M_{2}( \mathbb{C})$ such that $X^2=A$?