In some lecture notes I'm reading is said that the Maxwell distribution (for the speed of a particle in a gas)
$$f(\vec{v})= \left( \frac{m}{2 \pi k T} \right)^{3/2} \exp \left( - \frac{m}{2 k T} v^2 \right)$$
tends to zero faster than the inverse of any power of the speed (i.e. faster than $1/|v|^n$ for any $n$). No mathematical proof of this assertion is given, and I don't know how to demonstrate it. Any help would be greatly appreciated.
