\[ f(x) y'(x)+g(x) \text {tg}(y(x))+h(x)=0 \] ✗ Mathematica : cpu = 20.3533 (sec), leaf count = 0 , could not solve
DSolve[h[x] + g[x]*tg[y[x]] + f[x]*Derivative[1][y][x] == 0, y[x], x]
✗ Maple : cpu = 0. (sec), leaf count = 0 , could not solve
dsolve(f(x)*diff(y(x),x)+g(x)*tg(y(x))+h(x) = 0,y(x))