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Question Number 155533 by mnjuly1970 last updated on 01/Oct/21
     coefficiient of    x^( 60)  = ?       P = (x−1)(x^( 2) −1)(x^( 3) −1)...(x^( 15) −1)
$$ \\ $$$$\:\:\:{coefficiient}\:{of}\:\:\:\:{x}^{\:\mathrm{60}} \:=\:? \\ $$$$ \\ $$$$\:\:\:\mathrm{P}\:=\:\left({x}−\mathrm{1}\right)\left({x}^{\:\mathrm{2}} −\mathrm{1}\right)\left({x}^{\:\mathrm{3}} −\mathrm{1}\right)…\left({x}^{\:\mathrm{15}} −\mathrm{1}\right) \\ $$$$ \\ $$
Answered by qaz last updated on 02/Oct/21
(1/(2πi))∫_(∣z∣=ε) (((z−1)(z^2 −1)(z^3 −1)...(z^(15) −1))/z^(61) )dz
$$\frac{\mathrm{1}}{\mathrm{2}\pi\mathrm{i}}\int_{\mid\mathrm{z}\mid=\epsilon} \frac{\left(\mathrm{z}−\mathrm{1}\right)\left(\mathrm{z}^{\mathrm{2}} −\mathrm{1}\right)\left(\mathrm{z}^{\mathrm{3}} −\mathrm{1}\right)…\left(\mathrm{z}^{\mathrm{15}} −\mathrm{1}\right)}{\mathrm{z}^{\mathrm{61}} }\mathrm{dz} \\ $$

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