Calculating the residues at the poles of $f(z) = \frac{\tan(z) }{z^2 + z +1} $
Should one start by factoring the denominator ? Then using a theorem from complex analysis about the residues at the poles of functions of the form p(z)/q(z)?

I didn't create the proper deadline, but I would like to have this done ASAP.

Not possible, I accepted this because of deadline 23 hours I am outside ! You can delete the post of you want to

@ Aman R: A question can not be deleted after it has been accepted. Please submit a blank solution, and all funded will be refunded.

Okay thank you
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