Roots of a fourth order polynomial

Question

I am looking for the roots of $x^4=-1$, I have written $ -1 $ using Euler as $e^{j180}$. Therefore, $x=\pm e^{j45}$. But the fourth order equation should have two other roots, how can I get them?

What is j ? Please say for making edit. – N.S.JOHN Apr 24 '16 at 16:10 — N.S.JOHN, Apr 24 '16 at 16:10
Four roots form a square on unit circle. – Apr 24 '16 at 16:16 — , Apr 24 '16 at 16:16

score 0 · Answer 1 · answered Apr 24 '16 at 16:18

0

You can write it as $x^4=i^2$ thus $(x-i^{0.5})(x+i^{0.5})(x^2+i)=0$ can you get $4$ roots now.

answered Apr 24 '16 at 16:18

Archis Welankar

16,138

Roots of a fourth order polynomial

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