why is $\sqrt{-1} = i$ and not $\pm i$?
14633
What's the thing with $\sqrt{-1} = i$
12217
What is so special about $\alpha=-1$ in the integral of $x^\alpha$?
106911
Square root of $-1$ in the ring $\mathbb{R}[x]/\langle(x^2+1)^2\rangle$
124209
How is $\ln(-1) = i\pi$?
116043
Why is a raised to the power of Zero is 1?
41204
Why do I get one extra wrong solution when solving $2-x=-\sqrt{x}$?
96554
Why is $x^0 = 1$ except when $x = 0$?
68315
Why doesn't multiplying square roots of imaginary numbers follow $\sqrt{a} \times \sqrt{b} = \sqrt{ab}$?
126484
Why is $\Gamma\left(\frac{1}{2}\right)=\sqrt{\pi}$?
127727
De Moivre Complex Roots: Definition of $i$ or $\sqrt {-1}$
95449
What is the square root of "$i$"?
55094
How to show $i^{-1} = -i$?
3955
Square roots -- positive and negative
67588
Why does $|e^{ix}|^2 = 1$?
95057
Possible fake proof of $1= -1$
6650
Why $\sqrt{-1 \times -1} \neq \sqrt{-1}^2$?
16931
Can one do the maths of physics without using $\sqrt{-1}$?