1. The problem statement, all variables and given/known data Find d^2/dx^2 and both complex number forms for the complex number equation (1+icos(x))/(1-icos(y)) 2. Relevant equations 1. z=a+bi 2. re^itheta 3. The attempt at a solution I have multiplied both sides by 1+icosy and gotten as far as (1+icosx+icosy-cosxcosy)/(1+cos^2y) but am going in circles after that. None of the trig identities seem to get me anywhere either.