d/dx (3x^4) = 12x^3
d/dx (sin(2x)) = 2cos(2x) [chain rule]
d/dx (x^2 * e^x) = 2x e^x + x^2 e^x = e^x
(x^2 + 2x) [product rule]
d/dx (x / cos x) = [1*cos x - x*(-sin x)] /
cos^2 x = (cos x + x sin x) / cos^2 x [quo-
tient rule]
d/dx (sin(2x)) = 2cos(2x) [chain rule]
d/dx (x^2 * e^x) = 2x e^x + x^2 e^x = e^x
(x^2 + 2x) [product rule]
d/dx (x / cos x) = [1*cos x - x*(-sin x)] /
cos^2 x = (cos x + x sin x) / cos^2 x [quo-
tient rule]
