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1-z-6-1-dz-




Question Number 213451 by issac last updated on 06/Nov/24
∫  (1/(z^6 −1)) dz=??
$$\int\:\:\frac{\mathrm{1}}{{z}^{\mathrm{6}} −\mathrm{1}}\:\mathrm{d}{z}=?? \\ $$
Answered by Frix last updated on 06/Nov/24
∫(dz/(z^6 −1))=Σ_(k=1) ^4 I_k   I_1 =(1/6)∫(dz/(z−1))=((ln ∣z−1∣)/6)  I_2 =−(1/6)∫(dz/(x+1))=−((ln ∣z+1∣)/6)  I_3 =(1/6)∫((z−2)/(z^2 −z+1))dz=((ln (z^2 −z+1))/(12))−((√3)/6)tan^(−1)  ((2z−1)/( (√3)))  I_4 =−(1/6)∫((z+2)/(z^2 +z+1))dz=−((ln (z^2 +z+1))/(12))−((√3)/6)tan^(−1)  ((2z+1)/( (√3)))    ∫(dz/(z^6 −1))=  =(1/(12))ln (((z−1)^2 (z^2 −z+1))/((z+1)^2 (z^2 +z+1))) +((√3)/6)tan^(−1)  (((√3)z)/(z^2 −1)) +V
$$\int\frac{{dz}}{{z}^{\mathrm{6}} −\mathrm{1}}=\underset{{k}=\mathrm{1}} {\overset{\mathrm{4}} {\sum}}{I}_{{k}} \\ $$$${I}_{\mathrm{1}} =\frac{\mathrm{1}}{\mathrm{6}}\int\frac{{dz}}{{z}−\mathrm{1}}=\frac{\mathrm{ln}\:\mid{z}−\mathrm{1}\mid}{\mathrm{6}} \\ $$$${I}_{\mathrm{2}} =−\frac{\mathrm{1}}{\mathrm{6}}\int\frac{{dz}}{{x}+\mathrm{1}}=−\frac{\mathrm{ln}\:\mid{z}+\mathrm{1}\mid}{\mathrm{6}} \\ $$$${I}_{\mathrm{3}} =\frac{\mathrm{1}}{\mathrm{6}}\int\frac{{z}−\mathrm{2}}{{z}^{\mathrm{2}} −{z}+\mathrm{1}}{dz}=\frac{\mathrm{ln}\:\left({z}^{\mathrm{2}} −{z}+\mathrm{1}\right)}{\mathrm{12}}−\frac{\sqrt{\mathrm{3}}}{\mathrm{6}}\mathrm{tan}^{−\mathrm{1}} \:\frac{\mathrm{2}{z}−\mathrm{1}}{\:\sqrt{\mathrm{3}}} \\ $$$${I}_{\mathrm{4}} =−\frac{\mathrm{1}}{\mathrm{6}}\int\frac{{z}+\mathrm{2}}{{z}^{\mathrm{2}} +{z}+\mathrm{1}}{dz}=−\frac{\mathrm{ln}\:\left({z}^{\mathrm{2}} +{z}+\mathrm{1}\right)}{\mathrm{12}}−\frac{\sqrt{\mathrm{3}}}{\mathrm{6}}\mathrm{tan}^{−\mathrm{1}} \:\frac{\mathrm{2}{z}+\mathrm{1}}{\:\sqrt{\mathrm{3}}} \\ $$$$ \\ $$$$\int\frac{{dz}}{{z}^{\mathrm{6}} −\mathrm{1}}= \\ $$$$=\frac{\mathrm{1}}{\mathrm{12}}\mathrm{ln}\:\frac{\left({z}−\mathrm{1}\right)^{\mathrm{2}} \left({z}^{\mathrm{2}} −{z}+\mathrm{1}\right)}{\left({z}+\mathrm{1}\right)^{\mathrm{2}} \left({z}^{\mathrm{2}} +{z}+\mathrm{1}\right)}\:+\frac{\sqrt{\mathrm{3}}}{\mathrm{6}}\mathrm{tan}^{−\mathrm{1}} \:\frac{\sqrt{\mathrm{3}}{z}}{{z}^{\mathrm{2}} −\mathrm{1}}\:+{V} \\ $$

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