help for formula and proof of product of series

• February 26th 2009, 09:28 PM
qtpipi
help for formula and proof of product of series
http://img.photobucket.com/albums/v1...d/reasdfer.jpg

I can't figure out the formula, and without it I can't get much of a proof...

• February 27th 2009, 05:53 AM
tah
Quote:

Originally Posted by qtpipi
http://img.photobucket.com/albums/v1...d/reasdfer.jpg

I can't figure out the formula, and without it I can't get much of a proof...

Hi, notice $1-\frac{1}{i^2} = \frac{(i-1)(i+1)}{i^2}$, distribute the product and use the factorial notation.