henpen Group Title $\frac{d}{dx} \int_a^bf(x)dt=\int_a^b\frac{df(x)}{dx}dt$ Why is the equality correct? one year ago one year ago

1. henpen Group Title

http://en.wikipedia.org/wiki/Differentiation_under_the_integral_sign It's to do with this, but the article didn't help me much

2. phi Group Title

did you look at this http://en.wikipedia.org/wiki/Leibniz_integral_rule#Proof_of_basic_form

3. henpen Group Title

That's it. Thanks