how do you know (-1)^n(1+4^n/1+3^n) is a geometric series?

Question

anonymous · Answer

$$(-1)^n\frac{1+4^n}{1+3^n}$$

?  is that right?

anonymous · Answer

yeah

anonymous · Answer

idk how to prove that its a geometric series

anonymous · Answer

I am not sure if it is even a geometric series

what do you think @zarkon

anonymous · Answer

well they used a geometric series to compare it with, the answer diverges

anonymous · Answer

oh, that's different; it is called comparison test; this does not have to be geometric series for that

anonymous · Answer

let me know if you are still here

zarkon · Answer

you can also use the divergence test.  The limit of the sequence is not zero...therefore the series diverges

zarkon · Answer

and imranmeah91is correct....it is not geometric.

anonymous · Answer

|dw:1332465387707:dw| this is what they had used on a previous problem, so i figured id try the same method, but i dont knw how they used a geometric series to compare it with to get the answer, that is what that puzzles me, any ideas?