Hey there, I've just a quick question about numer 6 at the following link - http://titus.phy.qub.ac.uk/group/Jorge/AMA203/assignments/ass03_7.pdf [Broken] I'm normally okay with integrals but I'm a bit rusty on them at the mo (I haven't done a proper integral since May/June time, ooops!) and I'm convinced I'm doing something wrong here. For the first part (where the semicircle is in the upper half of the imaginary plane), I've let z=e^(itheta) so z*= e^(-itheta). Then to change the variable I've done dz/dtheta and got ie^(itheta). Since it moves around the upper half from x=1 to x= -1, I thought this would be equivalent to it going from 0 to pi. So I've calculated the integral (bottom limit=0 and upper limit=pi) and got i(pi) out of it. For the next one I wasn't sure if I was doing it right because it was going below the plane. I kept z=e^(itheta) since although the path was changing, I figured that since the angles we'd now be using would be negative, we could keep what looks like the same z as before. So I calculated it in the same way as the first part, except having my lower limit as 0 and my upper limit as -pi. In the end I got -i(pi) out of it. Can anyone check if those are okay or not? I guess I got confused at first because I expected thm to be equal, but then I think that z* isn't analytic so this isn't necessarily the case. If anyone could shed any light on it I'd be really grateful. Thanks.