Im trying to understand the contour when there are two poles on the real axis without poles on Im axis, because their residue cancle each other.
For residue of pole(-2)=-1, residue of pole(-1)=-1:
[math]I=\int_0^\infty\frac{dx}{(x+1)^2(x+2)}[/math]
For residue of pole(-2)=-1, residue of pole(-1)=-1:
[math]I=\int_0^\infty\frac{dx}{(x+1)^2(x+2)}[/math]