Why is $\sqrt{x^2}=|x|$ instead of $\pm x$?
3955
Square roots -- positive and negative
27888
Why is $|x|$ not differentiable at $x=0$?
118304
If $A^2 = I$ (Identity Matrix) then $A = \pm I$
66364
Why is $(\sqrt{2}+\sqrt{3})^{2008}$ so close to an integer?
150624
Why does the square root of a square involve the plus-minus sign?
25187
Why $∀x(P(x)→Q)$ is equivalent to $∃xP(x)→Q$
5528
Difference between $:=$ and $=$
157868
Is it wrong to say $ \sqrt{x} \times \sqrt{x} =\pm x,\forall x \in \mathbb{R}$?
33184
Something strange about $\sqrt{ 4+ \sqrt{ 4 + \sqrt{ 4-x}}}=x$ and its friends
114346
Why is $a^{-1}$ mod $p$ equal to $a^{p-2}$ mod $p$?
62485
How can I prove $\sqrt{2}^{\sqrt{2}^{\sqrt{2}^{\sqrt{2}^{\sqrt{2}...}}}}=2$
101326
My teacher describes absolute value confusingly: $|x|=\pm x,\quad \text{if}\enspace x>0 $.
19
Why is the square root of a sum not equal to the square root of each its addends?
100968
Why is $|e^{i \lambda z}| |e^{- \lambda y}|= |e^{- \lambda y}|$ here?
39457
Why is \[ ... \] preferable to $$ ... $$?
36664
How is the square root function implemented?
155136
$x\in \{\{\{x\}\}\}$ or not?