Ask your own question, for FREE!
Mathematics 9 Online
OpenStudy (anonymous):

Does the series converge or diverge. Use ratio test or root test.

OpenStudy (anonymous):

\[a_{1}=1, a_{n+1}=\frac{ 1+\ln(n) }{ n}a _{n}\]

OpenStudy (rational):

whats stopping you from using ratio test ?

OpenStudy (rational):

http://gyazo.com/1688af58da902d5b193507ae8862a768

OpenStudy (anonymous):

I dont know what to do with the an in an+1

OpenStudy (rational):

take the ratio and it goes away

OpenStudy (anonymous):

What would an be then?

OpenStudy (rational):

doesn't matter \[\large \lim\limits_{n\to \infty }\left|\dfrac{a_{n+1}}{a_n}\right| =\lim\limits_{n\to \infty }\left|\dfrac{\frac{1+\ln n}{n}a_n}{a_n}\right| = \lim\limits_{n\to \infty }\left|\dfrac{1+\ln n}{n}\right| \]

OpenStudy (anonymous):

wouldn't it just be infinity over infinity then?

OpenStudy (rational):

yes you may use L'hopital rule

OpenStudy (anonymous):

Okay, so it would be 1/n, which be equal 0, so the series is convergent?

OpenStudy (rational):

Yep!

OpenStudy (anonymous):

THANKS SO MUCH! :D

OpenStudy (rational):

yw

Can't find your answer? Make a FREE account and ask your own questions, OR help others and earn volunteer hours!

Join our real-time social learning platform and learn together with your friends!
Can't find your answer? Make a FREE account and ask your own questions, OR help others and earn volunteer hours!

Join our real-time social learning platform and learn together with your friends!