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1-n-1-1-n-H-n-n-2-2-1-




Question Number 189091 by mnjuly1970 last updated on 12/Mar/23
      1 :    Ω = Σ_(n=1) ^∞ (( (− 1 )^( n) H_( n) )/n^( 2) ) = ?      2 :     η (−1 )= ?
1:Ω=n=1(1)nHnn2=?2:η(1)=?
Answered by qaz last updated on 15/Mar/23
A=Σ(−1)^n H_n ∫_0 ^∞ xe^(−nx) dx  =−∫_0 ^∞ ((xln(1+e^(−x) ))/(1+e^(−x) ))dx=∫_0 ^1 ((lntln(1+t))/(t(1+t)))dt  =∫_0 ^1 (((lntln(1+t))/t)−((lntln(1+t))/(1+t)))dt  =∫_0 ^1 lnt(Li_2 (−t))′dt−∫_0 ^1 (((ln(t/(1+t))+ln(1+t))ln(1+t))/(1+t))dt  =−∫_0 ^1 ((Li_2 (−t))/t)dt−(1/3)ln^3 2−∫_0 ^1 ((ln(1−(1/(1+t)))ln(1+t))/(1+t))dt  =Li_3 (−1)−(1/3)ln^3 2−∫_0 ^1 (Li_2 ((1/(1+t))))′ln(1+t)dt  =Li_3 (−1)−(1/3)ln^3 2−Li_2 ((1/2))ln2+∫_0 ^1 ((Li_2 ((1/(1+t))))/(1+t))dt  =Li_3 (−1)−(1/3)ln^3 2−Li_2 ((1/2))ln2−∫_0 ^1 (Li_3 ((1/(1+t))))′dt  =Li_3 (−1)−(1/3)ln^3 2−Li_2 ((1/2))ln2−Li_3 ((1/2))+Li_3 (1)  =Li_3 (−1)−(1/3)ln^3 2−((π^2 /(12))−(1/2)ln^2 2)ln2−[(7/8)Li_3 (1)−(π^2 /(12))ln2+(1/6)ln^3 2]+Li_3 (1)  =Li_3 (−1)+(1/8)Li_3 (1)=(2^(1−3) −1)ζ(3)+(1/8)ζ(3)=−(5/8)ζ(3)  ...
A=Σ(1)nHn0xenxdx=0xln(1+ex)1+exdx=01lntln(1+t)t(1+t)dt=01(lntln(1+t)tlntln(1+t)1+t)dt=01lnt(Li2(t))dt01(lnt1+t+ln(1+t))ln(1+t)1+tdt=01Li2(t)tdt13ln3201ln(111+t)ln(1+t)1+tdt=Li3(1)13ln3201(Li2(11+t))ln(1+t)dt=Li3(1)13ln32Li2(12)ln2+01Li2(11+t)1+tdt=Li3(1)13ln32Li2(12)ln201(Li3(11+t))dt=Li3(1)13ln32Li2(12)ln2Li3(12)+Li3(1)=Li3(1)13ln32(π21212ln22)ln2[78Li3(1)π212ln2+16ln32]+Li3(1)=Li3(1)+18Li3(1)=(2131)ζ(3)+18ζ(3)=58ζ(3)
Commented by senestro last updated on 02/Apr/23

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