■πの級数公式(その38)
【1】その35
Σ1/64^n{16/(6n+1)+8/(6n+2)−2/(6n+4)−1/(6n+5)}
=32S(12,2)+16S(12,4)−4S(12,8)−2S(12,10)
=∫(0,1/√2)(64t+64t^3−64t^7−64t^9)/(1−t^12)dt
=64∫(0,1/√2)(t+t^3−t^7−t^9)/(1−t^12)dt
=64∫(0,1/√2)(t+t^3)/(1+t^6)dt
この定積分は結構面倒で,阪本ひろむ氏に計算をお願いした.ところが,
64∫(0,1/√2)(t+t^3)/(1+t^6)dt=32√3π/9
9/8Σ1/64^n(16/(6n+1)+8/(6n+2)−2/(6n+4)−1/(6n+5))=4√3π≠π^2
−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−
【2】その36
1/2^6Σ(−1)^n/2^10n(2^5/(4n+1)−1/(4n+3)+2^8/(10n+1)−2^6/(10n+3)−2^2/(10n+5)−2^2/(10n+7)+1/(10n+9))
=2^-15S(20,5)−2^-65S(20,15)+2^3S(20,2)−2S(20,6)−2^-3S(20,10)−2^-3S(20,14)+2^-5S(20,18)
=∫(0,1/√2)(10√2t^4−10√2t^14+16t−16t^5−4t^9−16t^13+16t^17)/(1+t^20)dt
これも
=∫(0,1/√2)(10√2t^4−10√2t^14+16t−16t^5−4t^9−16t^13+16t^17)/(1+t^20)dt≠π
であった.
−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−
【3】雑感
誤植があるのかもしれない.これ以上追求しないことにする.
===================================