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calculate-0-1-xlnx-x-1-dx-




Question Number 33677 by math khazana by abdo last updated on 21/Apr/18
calculate ∫_0 ^1   ((xlnx)/(x−1))dx .
calculate01xlnxx1dx.
Commented by math khazana by abdo last updated on 30/Apr/18
I =∫_0 ^1   (((x−1+1))/(x−1))ln(x)dx = ∫_0 ^1  ln(x)x +∫_0 ^1  ((lnx)/(x−1))dx  ∫_0 ^1  ln(x)dx=[xlnx −x]_(x→0) ^1  =−1  ∫_0 ^1   ((ln(x))/(x−1))dx=−∫_0 ^1 (Σ_(n=0) ^∞ x^n )ln(x)dx  =−Σ_(n=0) ^∞   ∫_0 ^1  x^n  ln(x)dx  by parts  A_n = ∫_0 ^1  x^n ln(x)dx=[(1/(n+1))x^(n+1) ln(x)]_0 ^1   −∫_0 ^1   (1/(n+1)) x^n dx =−(1/(n+1)) ∫_0 ^1  x^n dx=−(1/((n+1)^2 )) ⇒  ∫_0 ^1   ((xln(x))/(x−1))dx= −1+Σ_(n=0) ^∞   (1/((n+1)^2 )) =Σ_(n=1) ^∞  (1/n^2 )−1   ∫_0 ^1    ((xln(x))/(x−1))dx = (π^2 /6) −1 .
I=01(x1+1)x1ln(x)dx=01ln(x)x+01lnxx1dx01ln(x)dx=[xlnxx]x01=101ln(x)x1dx=01(n=0xn)ln(x)dx=n=001xnln(x)dxbypartsAn=01xnln(x)dx=[1n+1xn+1ln(x)]01011n+1xndx=1n+101xndx=1(n+1)201xln(x)x1dx=1+n=01(n+1)2=n=11n2101xln(x)x1dx=π261.

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