Problems with integration contours and residues

1. Hi there,

I have problems in finding the correct results for these integrals. I have to say I m not a great expert in residues...

2. Int[-inf;+inf;exp(-x^2)/(z-x)]

variable is x, constant is z

Int[-inf;0;exp(x)/(z-x)] with z<0

3. I think the 1st one gives 2i pi exp(-z^2) and the second one 2i pi exp(-z)+something