(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

The question:

a)Solve the equation [tex]z^{3}=4\sqrt{2}-4\sqrt{2}i.[/tex].

b)Express the answer in polar form.

3. The attempt at a solution

Here's what i got:

[tex]r=\sqrt{\left(4\sqrt{2}\right)^{2}+\left(-4\sqrt{2}\right)^{2}}=8[/tex]

[tex]\tan^{-1}\left(\frac{-4\sqrt{2}}{4\sqrt{2}}\right)=-45^{o}[/tex]

[tex]z^{3}=8^{3}cis\left(-45\cdot3\right)[/tex]

[tex]z^{3}=512\left(cos\frac{5\pi}{4}-i\sin\frac{5\pi}{4}\right)[/tex]

[tex]z^{3}=512\left(\frac{-\sqrt{2}}{2}+\frac{\sqrt{2}}{2}i\right)[/tex]

[tex]=-256\sqrt{2}+256\sqrt{2}i\right)[/tex]

im not sure if this is right, im supposed to graph this, and with these kinds of numbers, i figure i went wrong somewhere, i have no idea what they mean by"solve"and how or if this "solves" anything other than the fact that it ends with an equal sign, so if someone can check it for me id appreciate it, thanks."

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Not certain about Complex Number, Polar Form Question

**Physics Forums | Science Articles, Homework Help, Discussion**