17 Aug
2019
17 Aug
'19
3:22 p.m.
Hello, This identity seems true for some values of x. But we can delete x. Pi/4=sum(((2*n)!*(cosh(5/(x/sqrt(x^17+1)+1))/(cosh(5/(x/sqrt(x^17+1)+1))^2-1/2)-1/(sqrt(2)*(cosh(5/(x/sqrt(x^17+1)+1))^2-1/2)))^((2*n+1)/2)*cosh(((5/2)*(2*n+1))/(x/sqrt(x^17+1)+1)))/((2*n+1)*2^(4*n)*n!^2),n=0..inf); best ragard