I have a differential equation with boundary values that Mathematica solved for me. It gives me the solution in terms of Sinh and Cosh. Manually I change this into Sin and Cos using
Cosh(ix)=Cos(x) and Sinh(ix)/i=Sin(x).
Because I do this calculation often I'd like to do it within Mathematica. But I have no idea how, could someone help me?
Thank you for listening.