19/10/01 13:05:51.67 9+EG76aR.net
1/√(4+xx) = Σ[n=0,∞] 2(-1)^n C[2n,n] (x/4)^(2n),
をxで積分して
arcsinh(x/2) = Σ[n=0,∞] 2(-1)^n C[2n,n]/(2n+1) (x/4)^(2n+1)
= log[(x + √(xx+4))/2] = -log[(√(xx+4) - x)/4],
19/10/01 13:05:51.67 9+EG76aR.net
1/√(4+xx) = Σ[n=0,∞] 2(-1)^n C[2n,n] (x/4)^(2n),
をxで積分して
arcsinh(x/2) = Σ[n=0,∞] 2(-1)^n C[2n,n]/(2n+1) (x/4)^(2n+1)
= log[(x + √(xx+4))/2] = -log[(√(xx+4) - x)/4],