I don't know why but I keep doing this question but I keep getting the same wrong answer.
The question is:
Using Euler's formula, e^(ix) = cosx + isinx, show that if z=re^(ix), then:
1/z +1/(conjugate of z) = 2cosx/r^2
For some reason, I keep getting LHS = 2cosx/r instead of 2cosx/r^2