hi JacquesC, thanks for the reply.I want to solve for Mu. I tried to solve them but the solution came in terms of the root of polylog. But I could not evaluate them. Do you think that root of expressions containing polylog (di and tri) can be solved using Maple. BTW, the equation contains both the integrals. eq:=int(E^2/(exp((E-Mu)/KT)-1), E=El..EU))-int(E^2/(exp((E/KT)-1), E=EL..EU))=0