☰
d2jsp
Rules
Help
Forum Gold FAQ
Live Streams
Photo Gallery
Hourly Raffle
Ladder Slasher
Log In
Register
Log In
Register
Account Recovery
Resend Validation Email
d2jsp Forums
>
Off-Topic
>
General Chat
>
Homework Help
> Quick Series Problem
Add Reply
New Topic
New Poll
Views: 118
Replies: 2
Track Topic
Bloo_Guardian
Member
Posts: 5,207
Joined: Dec 6 2009
Gold
:
24,204.00
#1
Mar 15 2014 03:41pm
Series from 1 to infinity of
sin(1/n)
n^(2/3)
I know I'm supposed to use the comparison test but can't find another series to use. 1/n^(2/3) is divergent so that doesn't help...
feanur
Member
Posts: 16,662
Joined: Nov 24 2007
Gold
:
15,245.00
Trader:
Trusted
#2
Mar 15 2014 05:38pm
This serie converges.
Toward infinity, 1/n ~ 0 then sin(1/n) ~ 1/n.
Hence,
sin(1/n)
~
1
n^(2/3) n^(5/3)
and 1/n^(5/3) have a convergent serie.
What are you exactly asked for ?
This post was edited by feanur on Mar 15 2014 05:39pm
brmv
Member
Posts: 28,331
Joined: Jun 9 2007
Gold
:
11,700.00
#3
Mar 15 2014 06:38pm
'feanur' gave you the right answer, just would like to add that from the taylor series of sine you can see that sin(1/n) < 1/n so you can replace the "~" with a "<"
if you have to find what the series converges to you will in my opinion have to use the taylor series and fiddle around
Go Back To
Homework Help
Topic List
Add Reply
New Topic
New Poll
© 2003-2026 d2jsp
Contact