# Under root -i

wat is under root - i ???

Hurkyl
Staff Emeritus
Gold Member
Do you mean $\sqrt{-i}$? You can figure it out yourself! If $a + bi = \sqrt{-i}$, then what does the definition of square root tell you?

dextercioby
Homework Helper
HINT:

$$-i=e^{-\frac{i\pi}{2}+2k\pi} , \ k\in\mathbb{Z}$$

Daniel.

Gib Z
Homework Helper
Hey guys, dont post here often, i will more from now on. Anyway, dexter got that from the identity e^(ix)= cos x + i sin x.

will it be solved by the de mouvies theorm..........i dont think so...

dextercioby
Homework Helper
You mean "de Moivre". Yes, it will, since that theorem is a trivial consequence of the fact that

$$\left(e^{ix}\right)^{n}=e^{inx}$$

Daniel.

HallsofIvy