Question Number 114721 by mnjuly1970 last updated on 20/Sep/20
![....nice calculus.... prove that:: Φ=∫_(0 ) ^( 1) xln[ln(x).ln(1−x)]dx=−γ γ ::= euler mascheroni constant. ...m.n.july.1970...](https://www.tinkutara.com/question/Q114721.png)
Answered by maths mind last updated on 20/Sep/20
![by part =∫_0 ^1 (1−x)ln[ln(1−x)ln(x)]dx ⇔2∫_0 ^1 xln(ln(x)ln(1−x))dx=∫_0 ^1 ln[ln(x)ln(1−x)]dx =∫_0 ^1 ln(−ln(x).−ln(1−x))dx =∫_0 ^1 ln(−ln(x))dx+∫_0 ^1 ln(−ln(1−x))dx in 2nd 1−x=t⇒ =2∫_0 ^1 ln(−ln(x))dx t=−ln(x) =2∫_0 ^∞ ln(t)e^(−t) dt Γ(x)=∫_0 ^∞ t^(x−1) e^(−t) dt Γ′(1)=∫_0 ^∞ ln(t)e^(−t) dt=Ψ(1)=−γ ⇔2∫_0 ^1 xln[ln(x)ln(1−x)]dx=2∫_0 ^1 ln(−ln(x))dx=−2γ ⇒∫_0 ^1 xln[ln(x)ln(1−x)]dx=−γ](https://www.tinkutara.com/question/Q114727.png)
Commented by mnjuly1970 last updated on 20/Sep/20

Commented by maths mind last updated on 20/Sep/20

Answered by mnjuly1970 last updated on 20/Sep/20
![my solution.. Φ =∫_0 ^( 1) xln[(−ln(x))(−ln (1−x))]dx =∫_0 ^( 1) xln(−ln(x))dx +∫_0 ^( 1) xln(−ln(1−x))dx =∫_0 ^( 1) xln(−ln(x))dx +∫_0 ^( 1) (1−x)ln(−ln(x))dx =∫_0 ^( 1) ln(−ln(x))dx=^([−ln(x)=t]) −∫_∞ ^( 0) e^(−t) ln(t)dt =∫_0 ^( ∞) e^(−t) ln(t)dt = −γ ✓ m.n.july.1970](https://www.tinkutara.com/question/Q114736.png)