When |q| < 1 the series converge to
This is the case since
i'm supposed to tell if this converges or diverges, & if it converges, evaluate the sum
i know that cosine oscillates..but because it's cosine of a specific value, i'm a little confused. since cos 1 is about 1, will this just go up to infinity? and if so, how would i show it?
there's really no reason to be rude. it looks similar to the definition for the geometric series, where the sum converges to a/1-r, but not identical. i haven't seen the other form that running-gag posted, so i was just asking. i'm here to understand, if you don't want to help me, you don't have to.
And what is a in your formula ? It's the first term of the series ! (it should be better with a smilie ><)
Your series starts at k=0, and when k=0,
i'm sorry if you weren't trying to be, it just seemed like it because you were like "did you actually read it??" >.< i've had a couple of bad experiences on here, so, i just wanted to make sure. i appreciate your help, and, i agree that it's better when you don't give the answer right away. thanks again, sorry for the misunderstanding.
the series actually started at k=1, so, that's probably where i'm getting hung up..