Does NM=I give MN=I?
3301
If $AB = I$ then $BA = I$
81181
Prove that $\det(M-I)=0$ if $\det(M)=1$ and $MM^T=I$
29084
Largest integer that can't be represented as a non-negative linear combination of $m, n = mn - m - n$? Why?
103987
What does the square root of minus $i$ equal?
145248
Relation between Meissel–Mertens constant and Euler–Mascheroni constant
148993
Can the initial time be non-zero?
28057
Deriving $p = mv$ from translational symmetry (momentum conservation law)?
80004
Why is $1/i$ equal to $-i$?
26671
Does this seemingly elementary question require König's theorem?
102068
What's the difference between NMR and EPR?
81875
why is $\sqrt{-1} = i$ and not $\pm i$?
24860
What can $E=mc^2$ do?
144836
How to prove that $\frac{(mn)!}{m!(n!)^m}$ is an integer?
113628
Where M is a matrix calculate a formula for M^n
101706
What is the difference between i++ and ++i?
15175
When does a Möbius transformation map $\Im(z)>0$ to itself?
106584
If $A^{2n}=I$, then $A^n=\pm I$ where $A\in M_n(\mathbb{R})$