1. The problem statement, all variables and given/known data So, I actually have a bunch of these problems and I cannot do any of them. I don't think I'm really understanding it. Here is the question: (one of them) The way I wrote them, a_n means a sub n For each sequence a_n find a number k such that n^k a_n has a finite non-zero limit. (This is of use, because by the limit comparison test the series ∑from 1 to infinity (a_n) and ∑from 1 to infinity (n^-k) both converge or both diverge.) The question: a_n= (6+3n)^-7 What does k equal? 2. Relevant equations N/A 3. The attempt at a solution I'm actually 100% lost on this problem. I don't even know where to start :( Here's my attempt. It may not make any sense because I don't understand this. But here it is: (6+3n)^-7>0 1/(6+3n)^7>0 1>0 Ans: 1 But that is incorrect.