## tux Decide convergence/divergence from n=1 to infinity (2^n+1)/(3^n-1) 2 years ago 2 years ago

1. satellite73

converges for sure, and in fact i think the sum is not even 5

2. satellite73

ignore the irrelavent -1 and +1 and use the root test, get it right away

3. tux

It is hard to calculate using root test

4. satellite73

not when the index is in the exponent, then it is easy

5. satellite73

$\sqrt[n]{2^n}=2$!

6. tux

What to do with +1 and -1?

7. tux

Still have no idea how to do

8. Zarkon

if you want...you can use the comparison test

9. tux

Compare with (2/3)^n?

10. Zarkon

sure...use the limit comparison test then.