Use the fundamental theory of calculus to find the derivative

Question

Use the fundamental theory of calculus to find the derivative of 

f(x)= integral ((1/3)t²-1)⁵ dt with upper bound x² and lower bound 3 

f'(x)=

Answer 1

d/dx∫_a^u(x)f(t)dt = f(u(x))u'(x) = ((1/3)x⁴-1)⁵(2x)