✓ Mathematica : cpu = 0.0275229 (sec), leaf count = 19
DSolve[Sin[x]^2*y[x] - Cot[x]*Derivative[1][y][x] + Derivative[2][y][x] == 0,y[x],x]
✓ Maple : cpu = 0.162 (sec), leaf count = 15
dsolve(diff(diff(y(x),x),x)-diff(y(x),x)*cot(x)+y(x)*sin(x)^2=0,y(x))