I want to solve n ODE in Mathematica, but there is an error I cannot understand: "The function x appears with no arguments."
This is the code I used:
eqn = x''[y] + a x'[y] Sin[y - y0] + a x[y] (Cos[y - y0] - s) == 0; sol = DSolve[eqn, x, y]
Could anyone help me? Is there another function that solve the problem?