[math-fun] explicite...

Limit( (1/2^4)*product((sinh(2*n*k/(2*n+1))/(sinh(k))^(2*n/(2*n+1)))^(4*(-1)^(n)),n=1..infinity) ,k=infinity) = Limit ( (1/2^4)*product((sinh(2*n*k/(2*n+1))/(sinh(k))^(2*n/(2*n+1)))^(4*(-1)^(n)),n=1..infinity) , k=infinity) = 1/2^(Pi) ;