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dx-1-x-10-




Question Number 164171 by mkam last updated on 15/Jan/22
∫ (dx/(1+x^(10) ))
$$\int\:\frac{{dx}}{\mathrm{1}+{x}^{\mathrm{10}} } \\ $$
Answered by Ar Brandon last updated on 15/Jan/22
∫(dx/(1+x^(10) ))=∫Σ_(n=0) ^∞ (−x^(10) )^n dx=Σ_(n≥0) (((1)_n (−1)^n x^(10n+1) )/(n!(10n+1)))  =(x/(10))Σ_(n≥0) (((1)_n (−x^(10) )^n )/(n!(n+(1/(10)))))=(x/(10))Σ_(n≥0) (((1)_n Γ(n+(1/(10))))/(n!Γ(n+((11)/(10)))))(−x^(10) )^n   =(x/(100))Σ_(n≥0) (((1)_n ((1/(10)))_n )/(n!(((11)/(10)))_n ))(−x^(10) )^n =(x/(100))  _2 F_1 ((1/(10)), 1; ((11)/(10)); −x^(10) )+C
$$\int\frac{{dx}}{\mathrm{1}+{x}^{\mathrm{10}} }=\int\underset{{n}=\mathrm{0}} {\overset{\infty} {\sum}}\left(−{x}^{\mathrm{10}} \right)^{{n}} {dx}=\underset{{n}\geqslant\mathrm{0}} {\sum}\frac{\left(\mathrm{1}\right)_{{n}} \left(−\mathrm{1}\right)^{{n}} {x}^{\mathrm{10}{n}+\mathrm{1}} }{{n}!\left(\mathrm{10}{n}+\mathrm{1}\right)} \\ $$$$=\frac{{x}}{\mathrm{10}}\underset{{n}\geqslant\mathrm{0}} {\sum}\frac{\left(\mathrm{1}\right)_{{n}} \left(−{x}^{\mathrm{10}} \right)^{{n}} }{{n}!\left({n}+\frac{\mathrm{1}}{\mathrm{10}}\right)}=\frac{{x}}{\mathrm{10}}\underset{{n}\geqslant\mathrm{0}} {\sum}\frac{\left(\mathrm{1}\right)_{{n}} \Gamma\left({n}+\frac{\mathrm{1}}{\mathrm{10}}\right)}{{n}!\Gamma\left({n}+\frac{\mathrm{11}}{\mathrm{10}}\right)}\left(−{x}^{\mathrm{10}} \right)^{{n}} \\ $$$$=\frac{{x}}{\mathrm{100}}\underset{{n}\geqslant\mathrm{0}} {\sum}\frac{\left(\mathrm{1}\right)_{{n}} \left(\frac{\mathrm{1}}{\mathrm{10}}\right)_{{n}} }{{n}!\left(\frac{\mathrm{11}}{\mathrm{10}}\right)_{{n}} }\left(−{x}^{\mathrm{10}} \right)^{{n}} =\frac{{x}}{\mathrm{100}}\:\underset{\mathrm{2}} {\:}{F}_{\mathrm{1}} \left(\frac{\mathrm{1}}{\mathrm{10}},\:\mathrm{1};\:\frac{\mathrm{11}}{\mathrm{10}};\:−{x}^{\mathrm{10}} \right)+{C} \\ $$

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