Why is there root of -1?
11119
What are imaginary numbers?
14633
What's the thing with $\sqrt{-1} = i$
6622
How to find roots of $X^5 - 1$?
60869
Is induction valid when starting at a negative number as a base case?
28854
Modulus with a negative number
90043
Show that if $r$ is an nth root of $1$ and $r\ne1$, then $1 + r + r^2 + ... + r^{n-1} = 0$.
100465
Does there exist a continuous bijection from $(-1,1) \to (-1,1]$?
104410
Why do we omit the negative sign when finding basic angle when solving trigonometric equations?
106911
Square root of $-1$ in the ring $\mathbb{R}[x]/\langle(x^2+1)^2\rangle$
22397
Is 0.9999... equal to -1?
6128
If $a \cdot a = 1$ then $a = 1$ or $a = -1$
29909
Is there a reason some languages allow a negative modulus?
155285
difficulty of accepting $i^2 = -1$ for first timers
28502
How to solve $x^3=-1$?
16931
Can one do the maths of physics without using $\sqrt{-1}$?
3955
Square roots -- positive and negative
80648
What's $(-1)^{2/3}\; $?