Ratio test, why does the (-1)^(n+1) disappear?

[CinderBlockFist]

In the book while doing the ratio test:

as n --> infinity

why do they just have (-1)^(n+1) just disappear in the next step, since it oscillates between -1 and 1, I don't understand how u could just make it disappear in computations. Isn't the limit as n -> infinity , equal to D.N.E.?

[Cyrad2]

I believe the ratio test tests the absolute value of |An+1 / An|. so the (-1)^n and (-1)^n+1 will just be one, so u can just take it out.

[CinderBlockFist]

crap lol, i didn't even think of that. THanks cyrus, u da man!