Menu Close

Evaluate-0-1-li-2-x-1-x-dx-




Question Number 142791 by mnjuly1970 last updated on 05/Jun/21
   Evaluate:: ...         Ω :=∫_0 ^( 1)  ((li_2 ((√x) ))/(1+(√x))) dx=??      ...........
$$\:\:\:{Evaluate}::\:… \\ $$$$\:\:\:\:\:\:\:\Omega\::=\int_{\mathrm{0}} ^{\:\mathrm{1}} \:\frac{{li}_{\mathrm{2}} \left(\sqrt{{x}}\:\right)}{\mathrm{1}+\sqrt{{x}}}\:{dx}=?? \\ $$$$\:\:\:\:……….. \\ $$
Answered by Dwaipayan Shikari last updated on 05/Jun/21
2∫_0 ^1 ((uLi_2 (u))/(1+u))du  =2∫_0 ^1 Li_2 (u)du−2∫_0 ^1 ((Li_2 (u))/(1+u))du  =2Σ_(n=1) ^∞ (1/(n^2 (n+1)))−(π^2 /3)log(2)+(5/4)ζ(3)  =2Σ_(n=1) ^∞ (1/n^2 )−(1/(n(n+1)))−(π^2 /3)log(2)+(5/4)ζ(3)  =(π^2 /3)log((e/2))−2+(5/4)ζ(3)
$$\mathrm{2}\int_{\mathrm{0}} ^{\mathrm{1}} \frac{{uLi}_{\mathrm{2}} \left({u}\right)}{\mathrm{1}+{u}}{du} \\ $$$$=\mathrm{2}\int_{\mathrm{0}} ^{\mathrm{1}} {Li}_{\mathrm{2}} \left({u}\right){du}−\mathrm{2}\int_{\mathrm{0}} ^{\mathrm{1}} \frac{{Li}_{\mathrm{2}} \left({u}\right)}{\mathrm{1}+{u}}{du} \\ $$$$=\mathrm{2}\underset{{n}=\mathrm{1}} {\overset{\infty} {\sum}}\frac{\mathrm{1}}{{n}^{\mathrm{2}} \left({n}+\mathrm{1}\right)}−\frac{\pi^{\mathrm{2}} }{\mathrm{3}}{log}\left(\mathrm{2}\right)+\frac{\mathrm{5}}{\mathrm{4}}\zeta\left(\mathrm{3}\right) \\ $$$$=\mathrm{2}\underset{{n}=\mathrm{1}} {\overset{\infty} {\sum}}\frac{\mathrm{1}}{{n}^{\mathrm{2}} }−\frac{\mathrm{1}}{{n}\left({n}+\mathrm{1}\right)}−\frac{\pi^{\mathrm{2}} }{\mathrm{3}}{log}\left(\mathrm{2}\right)+\frac{\mathrm{5}}{\mathrm{4}}\zeta\left(\mathrm{3}\right) \\ $$$$=\frac{\pi^{\mathrm{2}} }{\mathrm{3}}{log}\left(\frac{{e}}{\mathrm{2}}\right)−\mathrm{2}+\frac{\mathrm{5}}{\mathrm{4}}\zeta\left(\mathrm{3}\right) \\ $$
Commented by mnjuly1970 last updated on 05/Jun/21
  tashakor and sepas mr payan...
$$\:\:{tashakor}\:{and}\:{sepas}\:{mr}\:{payan}… \\ $$

Leave a Reply

Your email address will not be published. Required fields are marked *