Why is $\sqrt{x^2} = |x|$?
77081
Proving square root of a square is the same as absolute value
117320
Why is this true: $\|x\|_1 \le \sqrt n \cdot \|x\|_2$?
22129
Why is $\sqrt{\sum_{i=1}^n |v_i|^2} \leq \sum_{i=1}^n |v_i|$ true?
14633
What's the thing with $\sqrt{-1} = i$
141945
Why is $f(x) = \sqrt{x}$ is continuous at $x=0$? Does $\lim_{x \to 0^{-}} \sqrt{x}$ exist?
6650
Why $\sqrt{-1 \times -1} \neq \sqrt{-1}^2$?
66364
Why is $(\sqrt{2}+\sqrt{3})^{2008}$ so close to an integer?
67605
Different proof that $\sqrt{2}$ is irrational
10774
Why $f(x) = \sqrt{x}$ is a function?
31327
Why is $\sqrt{x}$ a function?
17542
Why is $\sqrt{-x}*\sqrt{-x}=-x?$
105110
Why does $\sqrt{n\sqrt{n\sqrt{n \ldots}}} = n$?
3712
Why $\sqrt{-1 \cdot {-1}} \neq \sqrt{-1}^2$?
126484
Why is $\Gamma\left(\frac{1}{2}\right)=\sqrt{\pi}$?
101326
My teacher describes absolute value confusingly: $|x|=\pm x,\quad \text{if}\enspace x>0 $.
58212
Why doesn't the quadratic equation contain $2|a|$ in the denominator?
41204
Why do I get one extra wrong solution when solving $2-x=-\sqrt{x}$?