Math Is Fun Forum

zetafunc.

Guest

gamma function.

how do i use gamma function to calculate factorials of negative numbers and decimals? please tell me, for example, how to calculate 2.4!, with detailed working out and showing formula used if necessary. thank you.

I heard that 2.5! = 2.5*1.5*0.5*sqrt(pi), but I don't know why... my teacher doesnt tell me.

help

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: gamma function.

Hi zetafunc.

Yes, that is one way to calculate 2.5!

From the definition of the gamma function:

But this is not a good way to calculate these factorials.

my teacher doesnt tell me.

Your teacher probably doesn't know how to calculate them.

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.