
Jesse R. answered 06/24/20
The MathMAGICIAN: Patient and Engaging Tutor with Years of Experience
First we have a definite integral going from a constant to a function of x. If we can rewrite the problem to go from a constant to just x, then we can use the first fundamental theorem of calculus to find an answer.
f(x)= (2, x2) ∫ex^3dx
g(x) = (2,x) ∫ex^3dx (same except the bounds are now from a constant to x which allows the first fundamental theorem to be used)
Defining a similar function were the upper bound is just x then allows us to say f(x)=g(x2) which allows us to say that f'(x)=g'(x2)=g'(x2)*2x (by the chain rule) and g(x) is written so that we can easily take its derivative using the fundamental theorem which says the derivative of an integral from a constant to x is equal the the inside of the integral
g'(x) = ex^3
g'(x2)=e(x^2)^3=ex^6
so we know f'(x) = g'(x2)*2x
f'(x) = 2xex^6

Jesse R.
I did a bad job typing out the chain rule, sorry! It is easier to explain stuff like this with a video but they are currently unavailable06/24/20