- #1

littlewombat

- 7

- 0

**De Moivre's theorem~~HELP~**

## Homework Statement

Solve the following equations

z^3=-8i

Can anyone plz tell me how to solve this problem?

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- Thread starter littlewombat
- Start date

- #1

littlewombat

- 7

- 0

Solve the following equations

z^3=-8i

Can anyone plz tell me how to solve this problem?

- #2

Mentallic

Homework Helper

- 3,802

- 94

You can use De Moivre's theorem (actually, are you meant to?) but there is an easier way to solve it.

Notice that [tex]-8i=\left(2i\right)^3[/tex]

- #3

Apphysicist

- 108

- 0

## Homework Statement

Solve the following equations

z^3=-8i

Can anyone plz tell me how to solve this problem?

Z=cuberoot(-8i)

So write (-8i) in r*e^(i*theta) form and then raise it to the one-third...then consider all the angles that theta could be as you round the unit circle once.

EDIT: I like Mentallic's way, haha.

- #4

Mentallic

Homework Helper

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