Question

Question

0

785

4

+422

Find all complex numbers z such that z^4 = -4.

Note: All solutions should be expressed in the form a+bi, where a and b are real numbers.

So i know that z^4 = -4. I also know that z is a complex number. I dont really know what to do now! Can someone help a little pls!

AltShaka Apr 22, 2020

ElectricPavlov · Answer 1 · 2020-04-22T01:45:18

DO a search for this Q and answer.....it has been posted multiple times in recent months....

AltShaka · Answer 2 · 2020-04-22T01:46:23

+422

+1

May you please post a link since I didnt see any?

AltShaka Apr 22, 2020

+37146

0

I can't finsd it either....as I recall it was +-1 +- i (four solutions)

geno3141 · Answer 3 · 2020-04-22T02:24:43

Write -4 into r·( cos(theta) + i·sin(theta) ) form = 4( cos(180^o) + i·sin(180^o) )

Find one fourth root: 4^1/4 ( cos( 180^o / 4 ) + i·sin( 180^o / 4) ) = 1 + i

The other three roots are each a 90^o rotation from the previous root: -1 + i, -1 - i, i - i