prove that $A^2 = I $ implies that $A=I $ or $ A= -I $
118304
If $A^2 = I$ (Identity Matrix) then $A = \pm I$
110256
Let $a,b \in {\mathbb{Z_+}}$ such that $a|b^2, b^3|a^4, a^5|b^6, b^7|a^8 \cdots$, Prove $a=b$
115583
prove that $a^2(p-q)(p-r)+b^2(q-p)(q-r)+c^2(r-p)(r-q)\ge 0$
17032
If $ab=ba$, Prove $a^2$ commutes with $b^2$
11506
Alternative proof that $(a^2+b^2)/(ab+1)$ is a square when it's an integer
62850
Linear Algebra: If $A^3 = I$, does $A$ have to be $I$?
20964
Proof that $n^2 < 2^n$
7034
Prove that $A+I$ is invertible if $A$ is nilpotent
155579
Show that $End_A(A)$ = {$r_a$ | $a ∈ A$}
154327
$A^2X = X$ show that $AX = X$, if $A_{ij} > 0$ and $x_{i} > 0$
110826
prove that : $ i = \sqrt {-1}\ $
47313
What is $i^i$ and $(i^i)^i$
43913
Prove that if $A^*+A=AA^*$ then $A$ is normal
151806
Prove that $A^k = 0 $ iff $A^2 = 0$
36602
$a^m=b^m$ and $a^n=b^n$ imply $a=b$
115460
Proving $a\mid b^2,\,b^2\mid a^3,\,a^3\mid b^4,\ldots\implies a=b$ - why is my approach incorrect
103496
Show that $3p^2=q^2$ implies $3|p$ and $3|q$