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Question Number 141082 by mnjuly1970 last updated on 15/May/21
                         ........ nice  .......  calculus ........     𝛗:=Σ_(n=2) ^∞   ((ζ ( n ))/(n . 4^n ))=?
..nice.calculus..ϕ:=n=2ζ(n)n.4n=?
Answered by mindispower last updated on 15/May/21
Γ(x+1)ζ(x+1)=∫_0 ^∞ (t^x /(e^t −1))dt  φ=Σ_(n≥2) (1/(Γ(n))).(1/(n4^n ))∫_0 ^∞ (t^(n−1) /(e^t −1))dt  =(1/4)Σ_(n≥2) .(1/(Γ(n+1)))∫_0 ^∞ ((t/4))^(n−1) .(1/(e^t −1))dt  =(1/4)∫_0 ^∞ .(4/t).Σ_(n≥2) (((((t/4))^n )/(n!))).(1/(e^t −1))dt  =∫_0 ^∞ (1/t)(((e^(t/4) −1−(t/4))/(e^t −1)))dt  let f(α)=∫_0 ^∞ ((e^(αt) −1−αt)/(t(e^t −1)))dt  φ=f((1/4))  f(0)=0  f′(α)=∫_0 ^∞ ((te^(αt) −t)/(t(e^t −1)))dt=∫_0 ^∞ ((e^(αt) −1)/(e^t −1))dt,0≤α<1  f′(a)=∫_1 ^∞ ((t^a −1)/(t−1)).(dt/t)  =∫_0 ^1 (((1/t^a )−1)/(1−t)).dt  =∫_0 ^1 ((t^(−a) −1)/(1−t))dt=−∫_0 ^1 ((1−t^(−a) )/(1−t))dt,Ψ(x+1)=−γ+∫_0 ^1 ((1−t^x )/(1−t))  f′(a)=−Ψ(1−a)−γ  f(a)=log(Γ(1−a))−γa+c  f(0)=c=0  φ=f((1/4))=log(Γ((3/4)))−(γ/4)
Γ(x+1)ζ(x+1)=0txet1dtϕ=n21Γ(n).1n4n0tn1et1dt=14n2.1Γ(n+1)0(t4)n1.1et1dt=140.4t.n2((t4)nn!).1et1dt=01t(et41t4et1)dtletf(α)=0eαt1αtt(et1)dtϕ=f(14)f(0)=0f(α)=0teαttt(et1)dt=0eαt1et1dt,0α<1f(a)=1ta1t1.dtt=011ta11t.dt=01ta11tdt=011ta1tdt,Ψ(x+1)=γ+011tx1tf(a)=Ψ(1a)γf(a)=log(Γ(1a))γa+cf(0)=c=0ϕ=f(14)=log(Γ(34))γ4
Commented by mnjuly1970 last updated on 15/May/21
bravo bravo sir power...
bravobravosirpower
Commented by mindispower last updated on 15/May/21
withe pleasur Sir
withepleasurSir
Answered by mnjuly1970 last updated on 15/May/21
      Γ(x+1):= e^(−γx) Π_(n=1) ^∞ (e^(x/n) /(1+(x/n)))           ln(Γ(x+1)):=−γx+Σ_(n≥1) ((x/n)−ln(1+(x/n)))           ((ln(Γ(x+1)))/x):=−γ +Σ_(n≥1) ((1/n)−(1/x)Σ_(k=1) (((−1)^(k−1) x^k )/(k.n^k )))     :=−γ+Σ_(n≥1) (1/n)−Σ_(n≥1) Σ_(k≥1) (((−1)^(k−1) x^(k−1) )/(k.n^k ))    :=−γ+Σ_(n≥1) (1/n)−Σ_(k≥1) ((((−1)^(k−1) x^(k−1) )/k)Σ_(n≥1) (1/n^k ))    :=−γ+Σ_(n≥1) (1/n)−Σ_(k≥1) (((−1)^(k−1) x^(k−1) )/k)ζ(k)   =−γ +ζ(1)−ζ(1)+((ζ(2)x)/2)−((ζ(3)x^2 )/3)+...   =−γ+Σ_(k≥2) (((−1)^k x^(k−1) ζ(k))/k)   ((ln(Γ(x+1)))/x)=−γ+(1/x)Σ_(k≥2) (((−1)^k x^k ζ(k))/k)     ln(Γ(x+1))=−γx+Σ_(k≥2) (((−1)^k x^k ζ(k))/k)     x:=−(1/4) ⇒ ln(Γ(1−(1/4)))=(γ/4)+Σ_(k≥2)  (((ζ(k))/(k.4^k )) )              ln(Γ((3/4)))−(γ/4)=Σ_(k≥2)  (((ζ (k ))/(k . 4^( k) )) )
Γ(x+1):=eγxn=1exn1+xnln(Γ(x+1)):=γx+n1(xnln(1+xn))ln(Γ(x+1))x:=γ+n1(1n1xk=1(1)k1xkk.nk):=γ+n11nn1k1(1)k1xk1k.nk:=γ+n11nk1((1)k1xk1kn11nk):=γ+n11nk1(1)k1xk1kζ(k)=γ+ζ(1)ζ(1)+ζ(2)x2ζ(3)x23+=γ+k2(1)kxk1ζ(k)kln(Γ(x+1))x=γ+1xk2(1)kxkζ(k)kln(Γ(x+1))=γx+k2(1)kxkζ(k)kx:=14ln(Γ(114))=γ4+k2(ζ(k)k.4k)ln(Γ(34))γ4=k2(ζ(k)k.4k)
Commented by mindispower last updated on 15/May/21
sir are you student ?
sirareyoustudent?
Answered by Dwaipayan Shikari last updated on 15/May/21
ψ(z+1)=−γ+Σ_(n=2) ^∞ ζ(n)z^(n−1)   [log(Γ(z+1))]_0 ^(−(1/4)) =−∫_0 ^((−1)/4) γ+Σ_(n=2) ^∞ ∫_0 ^(−(1/4)) (−1)^n ζ(n)z^(n−1) dz  log(Γ((3/4)))=(γ/4)+Σ((ζ(n))/(n4^n ))  Σ((ζ(n))/(n4^n ))=log(Γ((3/4)))−(γ/4)
ψ(z+1)=γ+n=2ζ(n)zn1[log(Γ(z+1))]014=014γ+n=2014(1)nζ(n)zn1dzlog(Γ(34))=γ4+Σζ(n)n4nΣζ(n)n4n=log(Γ(34))γ4
Commented by mnjuly1970 last updated on 15/May/21
 very very nice  thank you mr payan...   taylor expansion of digamma..
veryverynicethankyoumrpayantaylorexpansionofdigamma..

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