a question about Cauchy integral formula

I'm new in the complex analysis and I'm stuck with this integral :


$I=\displaystyle \int_{|z|=4} \frac{\mathrm{d}z}{(z^2+9)(z+9)} $


the exercise is about Cauchy integral, I don't want the whole solution, just give me a hint (Please don't post fully worked solutions)




what I have done : using partial fraction we get :


$I=\displaystyle \frac{1}{90} \int_{|z|=4} \frac{1}{9+z} + \frac{(9-z)}{9+z^2} \mathrm{d}z$


I'm trying to do this : $\displaystyle \int_{|z|=4} \frac{\mathrm{d}z}{9+z} $.


but $|9|>4$, how to do the integration in this case ?






via Recent Questions - Mathematics - Stack Exchange http://math.stackexchange.com/questions/293533/a-question-about-cauchy-integral-formula

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