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let-gt-0-prove-that-n-0-1-n-n-0-1-x-1-1-x-dx-




Question Number 32026 by abdo imad last updated on 18/Mar/18
let α>0 prove that  Σ_(n=0) ^∞   (((−1)^n )/(n+α)) =∫_0 ^1   (x^(α−1) /(1+x))dx .
letα>0provethatn=0(1)nn+α=01xα11+xdx.
Commented by abdo imad last updated on 22/Mar/18
∫_0 ^1   (x^(α−1) /(1+x))dx = ∫_0 ^1 (Σ_(n=0) ^∞ (−1)^n x^n )x^(α−1) dx  = Σ_(n=0) ^∞  (−1)^n  ∫_0 ^1  x^(n+α−1) dx  =Σ_(n=0) ^∞  (−1)^n  [ (1/(n+α)) x^(n+α) ]_0 ^1  =Σ_(n=0) ^∞   (((−1)^n )/(n+α)) .
01xα11+xdx=01(n=0(1)nxn)xα1dx=n=0(1)n01xn+α1dx=n=0(1)n[1n+αxn+α]01=n=0(1)nn+α.

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