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

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SUMMARY

The discussion centers on the application of the ratio test in calculus, specifically addressing the treatment of the term (-1)^(n+1) during limit evaluation as n approaches infinity. Participants clarify that this term oscillates between -1 and 1, thus its absolute value is 1, allowing it to be disregarded in the limit computation. The ratio test focuses on the absolute value of the ratio |A(n+1) / A(n)|, which simplifies the analysis of convergence or divergence of series. This understanding is crucial for correctly applying the ratio test in mathematical analysis.

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

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