Just to point out, if you're doing partial fractions and you start seeing coefficients like 204, 340 - chances are that isn't the intended method. However, as the other two pointed out, this is practically a trivial problem if you're allowed to use Cauchy's Thorem, and there isn't any need to split it up to use CT. To be honest, this is the kind of level of difficulty you'd expect at A-Level if CT was covered. As with your previous questions, really you just need to show that the function is holomorphic inside, and on, the contour by showing that any singularity lies outside (which is straightforward here since the singularities clearly all have modulus >1) and the function is holomorphic everywhere else (which you rarely need to explicitely show in a complex analysis course - it's clear with this given that sin(z) and the denominator are holomorphic, so the product of the two will be whereever the denominator is non-zero).