Question

Please Help Me!!!

Answer 1

@Hero @dan815

Answer 2

\[(\cos \frac{ \pi }{4 }+i \sin \frac{ \pi }{ 4 })^{3}=\cos \frac{ 3\pi }{4 }+i \sin \frac{ 3\pi }{ 4 }\]

Answer 3

So it would be #1?

Answer 4

yep

Answer 5

Thank you

Answer 6

for general
\[(\cos x+i \sin x)^n=\cos nx +i \sin nx\]