How simplify sum sum(4*k^2/(1-2*k+2*k^2)/(1+2*k+2*k^2),k,1,inf); ? The correct answer is 1/2*%pi*tanh(1/2*%pi)=integrate(sin(x)/sinh(x),x,0,inf) Aleksas D -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://www.math.utexas.edu/pipermail/maxima/attachments/20120703/44bd716a/attachment.html>