d2jsp
Log InRegister
d2jsp Forums > Off-Topic > General Chat > Homework Help > Proving Convergence
Add Reply New Topic New Poll
Member
Posts: 15,275
Joined: Sep 30 2009
Gold: 1,790.00
Oct 11 2013 01:56pm
I'm studying for an Analysis Exam and came across this review problem that has me stumped.

Suppose that s_n converges to pi. Prove that there is a real number N such that if n > N, then s_n < (22/7)

I know the definition of convergence (Given epsilon>0, there exists some N such that if n>N, |s_n - s| < epsilon), but I don't know how to apply it
Member
Posts: 16,662
Joined: Nov 24 2007
Gold: 15,245.00
Trader: Trusted
Oct 11 2013 04:26pm
Since 22/7 > pi, just choose an epsilon > 0 such that pi + epsilon < 22/7

There exist N such that for every n>N, |s_n - pi| < epsilon, and that implies s_n < 22/7.
Member
Posts: 28,331
Joined: Jun 9 2007
Gold: 11,700.00
Oct 11 2013 04:30pm
Quote (TritonV8 @ 11 Oct 2013 19:56)
I'm studying for an Analysis Exam and came across this review problem that has me stumped.
Suppose that s_n converges to pi. Prove that there is a real number N such that if n > N, then s_n < (22/7)
I know the definition of convergence (Given epsilon>0, there exists some N such that if n>N, |s_n - s| < epsilon), but I don't know how to apply it


/hint 22/7 = 3.142857... and pi = 3.14159... from one point on the elements of the series will all be closer to pi than to 22/7

are you sure it says "real number N"?
Member
Posts: 15,275
Joined: Sep 30 2009
Gold: 1,790.00
Oct 11 2013 06:07pm
Quote (feanur @ Oct 11 2013 05:26pm)
Since 22/7 > pi, just choose an epsilon > 0 such that pi + epsilon < 22/7

There exist N such that for every n>N, |s_n - pi| < epsilon, and that implies s_n < 22/7.


Quote (brmv @ Oct 11 2013 05:30pm)
/hint 22/7 = 3.142857... and pi = 3.14159... from one point on the elements of the series will all be closer to pi than to 22/7

are you sure it says "realnumber N"?


awesome, thx guys.
and yes, it says real number
Go Back To Homework Help Topic List
Add Reply New Topic New Poll