What are the derivs + 2nd derivs of; 1) y = (cos x) / (1 + sin x) 2) y = x * sqrt of (9-x) 3) y = x^4 - 8x^3 + 18x^2 - 16x + 5 I did them, but my answers are all wonky and I wanna check if they're right please? [EDIT] never mind; google is a miracle worker.