Pi/8=sum(((-1)^n*(sqrt(cosh(t)^2+1)-cosh(t))^(2*n+1)*cosh((2*n+1)*t))/(2*n+1),n=0..infinity) ;
For allt
Pi/8=sum(((-1)^n*(sinh(t)-sqrt(sinh(t)^2-1))^(2*n+1)*sinh((2*n+1)*t))/(2*n+1),n=0..infinity) ;
t in ]1 ;infinity[
Pi/8=sum(((sqrt(sin(t)^2+1)-sin(t))^(2*n+1)*sin((2*n+1)*t))/(2*n+1),n=0..infinity);
t in]-Pi 0[; ]0 ; Pi[
