need some help on this complex number question

[lapis wagon]

What should I do next or what have I done wrong

[sharp pond]

First line is incorrect

(2cosx)^2(2isinx)^4

(4cos^2(x))(16sin^4(x))

Use the fact you wrote on the top right

[lapis wagon]

Thanks I’ll give it go

[sharp pond]

This will give you 64cos^2(x)sin^4(x)

[lapis wagon]

So I should work on the right side?

[sharp pond]

And also

$(z^n+z^{-n})=2cos(n\theta)$

[balmy patrol]

riad

[lapis wagon]

Ohhh I forgot about that

[sharp pond]

Yes

At the end you just divide by 2 because you want 32

[lapis wagon]

Thanks for the help

Have a good day

[sharp pond]

You too