30.3 Gamma
The gamma function, \(\Gamma(x)\), is the generalization of the factorial function to continuous variables, defined so that for positive integers \(n\), \[ \Gamma(n+1) = n! \] Generalizing to all positive numbers and non-integer negative numbers, \[ \Gamma(x) = \int_0^{\infty} u^{x - 1} \exp(-u) \, du. \]