# Math Help - tricky integral

1. ## tricky integral

How do you use the fundamental theorem of calculus compute

$\frac{d}{db} \int_{0}^{b} b f(x) dx$

2. Originally Posted by soloakewlstick
How do you use the fundamental theorem of calculus compute

$\frac{d}{db} \int_{0}^{b} b f(x) dx$
there's nothing tricky about the question! use product rule. the answer is: $bf(b) + \int_0^b f(x) dx.$

3. thanks!