differentiate y = 4x^3(12e^-4x) with respect to x

y = 4x³e^-4x   u = 4x³  v = e^-4x du/dx = 12x² dv/dx = -4e^-4x using the product rule; vdu +udv  vdu + udv = 12x²e^-4x - 16x³e^-4x