Gamma Function of One Half/Proof 2

Theorem

 * $\Gamma \left({\dfrac 1 2}\right) = \sqrt \pi$

where $\Gamma$ denotes the Gamma function.

Proof
From Euler's Reflection Formula:


 * $\forall z \notin \Z: \Gamma \left({z}\right) \Gamma \left({1 - z}\right) = \dfrac \pi {\sin \left({\pi z}\right)}$

Setting $z = \dfrac 1 2$: