d/dx [x^n] = n*x^(n-1)
d/dx [f(x) + g(x)] = f'(x) + g'(x)
d/dx [c] = 0 (where c is a constant)
d/dx [f(x) * g(x)] = f(x) * g'(x) + g(x) * f'(x)
d/dx [f(x) / g(x)] = (f'(x) * g(x) - f(x) * g'(x)) / [g(x)]^2