If you look at the Taylor series link, you can see the sum representations of trigonometric functions. So for instance, the 3/5/7 is just the (2n+1) value. Th

If you look at the Taylor series link, you can see the sum representations of trigonometric functions. So for instance, the 3/5/7 is just the (2n+1) value. The other looks like the sum of the product of (2n-1)/(2n) for values 1 to n.