# Math Help - Variable limits of intergration

1. ## Variable limits of intergration[resolved]

okay I know that d/dxf(t)dt from a to x is f(x) but what happens if x is the lower limit instead of the upper limit? So from x to a. Does it become negative? Thanks.

2. Yes by simple property $\int_{a}^{b}{f}=-\int_{b}^{a}{f}.$

3. cool. thanks.