N-Ball
#Math
$\displaystyle V_{n\text{-ball boundary}}=C_{n}r^{n-1},, C_{n}=n \frac{\pi^{n/2}}{\Gamma\left( \frac{n}{2}+1 \right)}$
Derivation (in response to 3b1b Video):




- $\displaystyle \Gamma\left( \frac{n}{2}+1 \right)=\left( \frac{n}{2} \right)! \rightarrow C_{n}=n \frac{\pi^{n/2}}{\Gamma\left( \frac{n}{2} +1\right)}$