Hey guys, I am having difficulty with this problem so please help, and here it is.

edit: I don't know how to type this problem in it's original format so please bear with it.

E (sigma sign), with an infinite sign above it and with 'i'=0 below it. Then to its right is the equation 3i + 5/4i.

How would I find the initial value a1 and the 'r' value? This is a sum of the infinite geometric series problem.

Any help of feedback would be greatly appreciated, thanks.