Gamma function

The Gamma function is a function which may be used to extend the concept of factorial to complex numbers. If the real part of the complex number z is positive, one can define

		∞
	Γ ( z ) =	∫	tz-1 e-t   dt
		0

and show that

Γ(z+1) = z Γ(z).

Because of Γ(1) = 1, this relation implies Γ(n+1) = n! for all natural numbers n. It can further be used to extend the definition of Γ(z) to all complex numbers z except z = 0, -1, -2, -3, ...

/Talk