we can write now apply the root test, what do you get?
as for the second one, we can consider the following bounding:
I have this issue about some sums:
It must be divergent because but I cant show that, any idéas?
Ohh yeah I tried with but that didn´t really lead me anywhere,
And the second one is
I get it to converge to 0 because the denominator goes towards infinity so much faster, but the books answer is 1. Dont know how to get that.
Any ideas what I am doing wrong?
The books answer is .
How do I go from to ?
Also my root test turned up like this, first time so no
And here I´m stuck If I multiply by i get so that didn´t work
But hey still have other algebraic idéas. Lets multiply by ..and that gives me the original expression to the k:th root multiplied by 3...well....nja that doesnt help....(exept that I understand that if then the limit is smaller then 1 and the series converges. Well great thats what I want to find out by still, im back where I started....lets try something else..and here I´m stuck....