- #1
Jbreezy
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Homework Statement
Hi,
The question wanted to know if the alternating series converges or diverges.
$$A_n = \sum_{n=1}^\infty \frac{(-1)^{n+1}}{n+1}$$
Homework Equations
3. The Attempt at a Solution [/b
You can see it here .
http://www.calcchat.com/book/Calculus-ETF-5e/ chapter 9, section 5, question 11
So I understand the process I just want to know why they ignore the $$ (-1)^{n+1}$$ in the numerator all of a sudden it just becomes 1.
I understand that it will be either 1 or -1 depending on the value of n. But why can they just ignore if it was -1 and say it is 1 and take the limit? I don't get it.