I wanted to integrate $\phi$ with respect to $\eta$. But Mathematica cannot perform the integration. The problem is with the $\sinh$ function but I could not replace it with any simple function except nonlinear model fit which I don't want to do. Can somebody help to perform the integration by doing, may be, some simplification in $\phi$? phi=-((5 Sqrt[ 3] (5/4 - 3/4 Cos[2 eta]) Sech[Log[3]/ 2] (Sqrt[1 - sinalp^2] Cos[eta] (1/4 - 3/4 Cos[2 eta]) + 1/2 sinalp (-(11/4) - 3/4 Cos[2 eta]) Sin[eta...
