Infinite Product

1. Jan 25, 2008

end3r7

Essentially I need to find (if possible) the following infinite product

$$1 - \frac{1}{2*n^{2}}$$

So, not quite Wallis number. I must say that I'm at a complete loss, not even sure where to begin.

2. Jan 25, 2008

end3r7

0.358486649396841... is approximately what the number is (thanks to Matlab).

Looks like anything to you guys?

3. Jan 25, 2008

Hurkyl

Staff Emeritus
That looks awfully similar to the infinite product for sin z.

4. Jan 25, 2008

Rainbow Child

Which is

$$\sin(\pi\,z)=\pi\,z \prod_{n=1}^\infty\left(1-\frac{z^2}{n^2}\right)$$

5. Jan 25, 2008

end3r7

I'm not familiar, what does it look like?

6. Jan 25, 2008

end3r7

Thanks guys =)