L' Hopital's Rule. Product Rule for the denominator. Fundamental Theorem of Calculus to differentiate the integrals. Don't forget that the bounds are functions of ##x##, so apply Chain Rule (Leibniz's Rule).
After the first step, you'll end up with an expression that I'll call ##L##. Find and simplify ##L^{-1}## with a further application of all those rules. Then deduce what ##L## should be at the limit.