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Q31Section II (Mathematics)31 of 180

Argument principle — integrating P′/PP'/P around all the roots

If all roots of the polynomial 1+z+z2+⋯+z101+z+z^2+\dots+z^{10} are in the disk B(0,R)B(0,R), then:

∮∣z∣=R1+2z+3z2+⋯+10z91+z+z2+⋯+z10 dz=?\oint_{|z|=R}\frac{1+2z+3z^2+\dots+10z^9}{1+z+z^2+\dots+z^{10}}\,dz = ?

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