A matrix $R$ where $R\neq I$ but $R^7=I$
49855
Need a matrix to seventh power which is the identity but the original is not or the negative identity
73697
Let $A, B$ be $n\times n$ with $n\ge 2$ nonsingular matrices with real entries such that $A^{-1} + B^{-1} =(A+B)^{-1}$
108589
The inverse of the matrix $\{1/(i+j-1)\}$
68552
Find the representing matrix with the respect to the standard basis
11857
$A$ be a complex $3\times 3$ matrix such that $A^3=-I$
64644
An $r\times r$ submatrix of independent rows and independent columns is invertible (Michael Artin's book).
58021
Finding matrix $B$ is not zero matrix where $AB= 0$
31186
Hermitian matrix such that $4M^5+2M^3+M=7I_n$
144357
Choose $\rho$ such that $\rho$-norm minimizes the matrix condition number
151526
Determinant of a matrix with different cases for its entries
52946
If $X$ is an orthogonal matrix, why does $X^TX = I$?
70157
Is every matrix $A$ such that $A^k=I$ diagonalizable?
109736
For a 2x2 matrix A satisfying $A^k=I$, compute $e^A$
1906
Multiplying by a $1\times 1$ matrix?
127719
Is the matrix $R$ in the $QR$ decomposition unique?
57296
A non-diagonal $4\times4$ matrix such that $A^3=A^2=0$ and its rank is $2$
129564
Show that $A$ is an invertible matrix if $\left(A+I\right)^3=0$ and find $A^{-1}$