imaginary numbers

[umbral temple]

I need help with this, what do i do next , how do i continue?

[umbral temple]

In the question i need to determine Im and Re parts

I understand that it may be a fairly easy but i got stuck at it and dont know how to move on…

[drifting onyx]

Hint: put it in polar form

[umbral temple]

As i am not an english speaker what exactly do you mean by polar form

Like with sin&cos ?

[glass stone]

Yeah

z = r(cosθ+isinθ)

[drifting onyx]

Yes

Something useful: $(\cos{\theta}+i\sin{\theta})^n=\cos(n\theta)+i\sin(n\theta)$

[proven girder]

SWR

[umbral temple]

Is this correct?

[proven girder]

adonhs

[umbral temple]

Re and Im for (z-i)^9

[ancient saddle]

from where did you get the 90° ?

[umbral temple]

Oh my bad i meant 9θ not 90°

[ancient saddle]

ok

so you substituted z-i = z?