Can't do complex numbers question (1 Viewer)

[dangerousdave]

Can someone who is good at 4 unit please do this question for me?
I can't even start the question.

 

[Estel]

Well I don't fit your criteria... but I'll do it anyway

(1+cosx+isinx)^n
= (2cos^2(x/2)+i2sin(x/2)cos(x/2))^n
= 2^ncos^n(x/2)(cos(x/2)+isin(x/2))^n
= 2^ncos^n(x/2)(cos(nx/2)+isin(nx/2))

 

[dangerousdave]

I'm confused about the (x/2). Where the hell does that come from?

 

[Estel]

double angle formulae.

 

[withoutaface]

Well I don't fit your criteria... but I'll do it anyway

 

[Trefoil]

i.e.:
1+cos2a+sin2a
cos^2 a - sin^2 a +2sinacosa + 1
cos^2 + 2sinacosa
let 2a = b
cos^2(b/2) + 2sin(b/2)cos(b/2)

 

[Estel]

I'll retract my statement if all goes well in 13 months time.

 

[withoutaface]

I'll retract my statement if all goes well in 13 months time.

You'll kill it. What is of your most concern is that you must beat slide rule.:uhhuh:

 

[velox]

he better. Slide is annoying yet eager.