1. The problem statement, all variables and given/known data If tan-1z = (1/2i)ln[(1+iz)/(1-iz)] then find tan-1[(2sqrt(3) - 3i)/7] 3. The attempt at a solution I haven't gotten very far, but this is what I have so far: tan-1[(2sqrt(3) - 3i)/7] = (1/2i)ln[(i2sqrt(3) + 10)/(i2sqrt(3) + 4)] Where do you go from there? I'm not completely familiar with the rules of complex logarithms. Can you split it into real and imaginary parts?