Question Number 161830 by EnterUsername last updated on 22/Dec/21
$$\int\frac{{dx}}{\:\sqrt{\mathrm{1}−{x}^{\mathrm{14}} }} \\ $$
Answered by Ar Brandon last updated on 22/Dec/21
$$\mathrm{arcsin}\left({x}\right)=\underset{{n}=\mathrm{0}} {\overset{\infty} {\sum}}\frac{{x}^{\mathrm{2}{n}+\mathrm{1}} \left(\frac{\mathrm{1}}{\mathrm{2}}\right)_{{n}} }{{n}!\left(\mathrm{2}{n}+\mathrm{1}\right)}\Rightarrow\mathrm{arcsin}\left({x}^{\mathrm{7}} \right)=\underset{{n}=\mathrm{0}} {\overset{\infty} {\sum}}\frac{{x}^{\mathrm{14}{n}+\mathrm{7}} \left(\frac{\mathrm{1}}{\mathrm{2}}\right)_{{n}} }{{n}!\left(\mathrm{2}{n}+\mathrm{1}\right)} \\ $$$$\Rightarrow\frac{\mathrm{7}{x}^{\mathrm{6}} }{\:\sqrt{\mathrm{1}−{x}^{\mathrm{14}} }}=\mathrm{7}\underset{{n}=\mathrm{0}} {\overset{\infty} {\sum}}\frac{{x}^{\mathrm{14}{n}+\mathrm{6}} \left(\frac{\mathrm{1}}{\mathrm{2}}\right)_{{n}} }{{n}!}\Rightarrow\frac{\mathrm{1}}{\:\sqrt{\mathrm{1}−{x}^{\mathrm{14}} }}=\underset{{n}=\mathrm{0}} {\overset{\infty} {\sum}}\frac{\left(\frac{\mathrm{1}}{\mathrm{2}}\right)_{{n}} }{{n}!}{x}^{\mathrm{14}{n}} \\ $$$${I}=\int\frac{{dx}}{\:\sqrt{\mathrm{1}−{x}^{\mathrm{14}} }}=\int\underset{{n}=\mathrm{0}} {\overset{\infty} {\sum}}\frac{\left(\frac{\mathrm{1}}{\mathrm{2}}\right)_{{n}} }{{n}!}{x}^{\mathrm{14}{n}} {dx}=\underset{{n}=\mathrm{0}} {\overset{\infty} {\sum}}\frac{\left(\frac{\mathrm{1}}{\mathrm{2}}\right)_{{n}} }{{n}!\left(\mathrm{14}{n}+\mathrm{1}\right)}{x}^{\mathrm{14}{n}+\mathrm{1}} \\ $$$$\:\:\:=\frac{{x}}{\mathrm{14}}\underset{{n}=\mathrm{0}} {\overset{\infty} {\sum}}\frac{\left(\frac{\mathrm{1}}{\mathrm{2}}\right)_{{n}} }{{n}!\left({n}+\frac{\mathrm{1}}{\mathrm{14}}\right)}{x}^{\mathrm{14}{n}} =\frac{{x}}{\mathrm{14}}\underset{{n}=\mathrm{0}} {\overset{\infty} {\sum}}\frac{\left(\frac{\mathrm{1}}{\mathrm{2}}\right)_{{n}} \Gamma\left({n}+\frac{\mathrm{1}}{\mathrm{14}}\right)}{{n}!\Gamma\left({n}+\frac{\mathrm{15}}{\mathrm{14}}\right)}{x}^{\mathrm{14}{n}} \\ $$$$\:\:\:=\frac{{x}}{\mathrm{14}}\centerdot\frac{\Gamma\left(\frac{\mathrm{1}}{\mathrm{14}}\right)}{\Gamma\left(\frac{\mathrm{15}}{\mathrm{14}}\right)}\underset{{n}=\mathrm{0}} {\overset{\infty} {\sum}}\frac{\left(\frac{\mathrm{1}}{\mathrm{2}}\right)_{{n}} \left(\frac{\mathrm{1}}{\mathrm{14}}\right)_{{n}} }{{n}!\left(\frac{\mathrm{15}}{\mathrm{14}}\right)_{{n}} }{x}^{\mathrm{14}{n}} ={x}\underset{\mathrm{2}} {\:}{F}_{\mathrm{1}} \left(\frac{\mathrm{1}}{\mathrm{2}},\frac{\mathrm{1}}{\mathrm{14}};\frac{\mathrm{15}}{\mathrm{14}};{x}^{\mathrm{14}} \right) \\ $$
Commented by Lordose last updated on 22/Dec/21
$$\mathrm{fast} \\ $$
Commented by Ar Brandon last updated on 22/Dec/21