I need to use this theorem as part of a proof. Basically it goes as follows:
If $f(x_0) > g(x_0)$ and $\frac{d}{dx} f(x) > \frac{d}{dx} g(x)$ for all $x \geq x_0$, then $f(x) > g(x)$ for all $x\geq x_0$.
What's the name of this theorem, if it has one? Or if it doesn't, is there a simple way to prove it that I could include in my proof? Thanks.