find the derivative of f(x)=((x^2+3)^5+x)^2 using the chain rule.
I know that I would start with
f'(x)=2((x^2+3)^5+x) but I don't know how to do the rest
The answer is
f'(x)=2((x^2+3)^5+x)[5(x^2+3)^4(2x)+1]
I don't understand where the +1 at the end comes from