For the ratio test:
Is (2n-1) + 1 = 2n?
I have to use the ratio test to evaluate n2/(2n-1)! where n=1 for an infinite series...exam in a few hrs!
yes...this should be simple algebra for someone dealing with series. and what does this have to do with the ratio test?
do you mean $\displaystyle \frac {n^2}{(2n - 1)!}$?I have to use the ratio test to evaluate n2/(2n-1)! where n=1 for an infinite series...exam in a few hrs!
if so, we want to see if $\displaystyle \lim \left| \frac {\frac {(n + 1)^2}{(2n + 1)!}}{\frac {n^2}{(2n - 1)!}} \right| = \lim \left| \frac {(n + 1)^2}{n^2} \cdot \frac {(2n - 1)!}{(2n + 1)!} \right|< 1$
if so, the series $\displaystyle \sum \frac {n^2}{(2n - 1)!}$ converges absolutely
by the way, what you wanted was 2(n + 1) - 1 = 2n + 1, not what you said before