Beta
From specialfunctionswiki
$$B(x,y)=\displaystyle\int_0^1 t^{x-1}(1-t)^{y-1}dt$$
Theorem: $B(x,y)=\dfrac{\Gamma(x)\Gamma(y)}{\Gamma(x+y)}$
Proof: █
Theorem: $B(x,y)=B(y,x)$
Proof: █
Theorem: (i) $B(x+1,y)=\dfrac{x}{x+y} B(x,y)$
(ii) $B(x,y+1)=\dfrac{y}{x+y}B(x,y)$
Proof: █
Bell. Special Functions