Print 

Author Topic: Math problem lol  (Read 3417 times)

Offline BFM_Fénix

  • BFM Admin
  • *
  • Posts: 1396
  • I shall be reborn from the ashes
Math problem lol
« on: June 03, 2009, 07:10:40 PM »
Hey, i recently finished the semester (yeah!!!!!!!!) but i have a question: can anyone solve this?

infinity
S (n+2)!(n)2/n!(n2-1)
n=1

infinity
S (-1)n(x)2n+1/(2n+1)!
n=1

They are mathematical series problems. any comment will be precciated :)  :LOL:
*I think both are easy  :winkgrin:*

 :evil:

UPS, forgot something. Say if the series converge or diverge. If converge please give me the result. GL i honestly hope someone will know this, have fate in u
2000th member of the BFM forums.
According to Hlao, and Hlao's word is law.


Offline Goalie

  • Posts Too Much
  • *****
  • Posts: 2462
  • Congrats Jordan Lynch, 3rd place in Heisman!!!
    • York Set/Tech Crew
Re: Math problem lol
« Reply #1 on: June 03, 2009, 08:07:15 PM »
Top one will diverge, bottom one will converge.

That's all I can help with.  If I had some more time, I would try and solve it, but i don't right now.  Maybe one of our resident mathmaticians can help you.
You blame me?  Remember it had to get past 10 other players before I saw the ball.

Thanks to Spidey for this sig!                                                                                                                  .

Offline BFM_Edison

  • Captain
  • *
  • Posts: 3074
Re: Math problem lol
« Reply #2 on: June 03, 2009, 10:02:36 PM »
First diverges and second converges to sin(x) - x. Second one is the taylor series for sin(x) without the x term, hence the sin(x) - x.
52.87   60.07   46.40   72.73   68.23   55.10   98.27   84.73

Offline Haunted

  • Posts Too Much
  • *****
  • Posts: 1378
    • ummm..
Re: Math problem lol
« Reply #3 on: June 04, 2009, 10:10:38 AM »
*looks at jim*

;D by me ;D


;D Thanks Hlao! ;D


;D Thanks Spood! ;D

Offline UCANTSEEME

  • Senior Poster
  • ****
  • Posts: 777
  • Mnid pwoer is the olny way to sccuses.
Re: Math problem lol
« Reply #4 on: June 04, 2009, 10:12:40 AM »
*looks at jim*

and

*scratches his head*

Sig by Hlao




Big thanks to Geekums and Slayton for the sig!

Offline BFM_Fénix

  • BFM Admin
  • *
  • Posts: 1396
  • I shall be reborn from the ashes
Re: Math problem lol
« Reply #5 on: June 04, 2009, 10:33:01 AM »
Thx for giving the rigth answer, it was a debate with a friend of mine. He didnt believe me those were the real answers (maybe because i never went to math class or the ! played with his mind lol)
2000th member of the BFM forums.
According to Hlao, and Hlao's word is law.


Offline jim360

  • Posts Too Much
  • *****
  • Posts: 6847
Re: Math problem lol
« Reply #6 on: June 04, 2009, 10:55:37 AM »
*looks at jim*

Since Edison's answer looks right (and for the second one is exactly right) I can't see the reason to post myself.

Applying D'alambert's ratio test to the first series is enough to show that it diverges since as n tends to infinity an+1/an tends to 1+O(1/n) which is greater than 1.
Check out my Short introduction... corner and my "Historical figures who should perhaps be better-known" thread!!

Exciting videos: 1.1 / 1.2 / 2 / 3 / 4 / 5 / 6



              

Offline Haunted

  • Posts Too Much
  • *****
  • Posts: 1378
    • ummm..
Re: Math problem lol
« Reply #7 on: June 05, 2009, 09:36:40 AM »
*looks at jim*

Since Edison's answer looks right (and for the second one is exactly right) I can't see the reason to post myself.


and he posts anyway  ;D the spammer.. lol

;D by me ;D


;D Thanks Hlao! ;D


;D Thanks Spood! ;D

Offline BFM_Edison

  • Captain
  • *
  • Posts: 3074
Re: Math problem lol
« Reply #8 on: June 05, 2009, 12:45:44 PM »
*looks at jim*

Since Edison's answer looks right (and for the second one is exactly right) I can't see the reason to post myself.

Applying D'alambert's ratio test to the first series is enough to show that it diverges since as n tends to infinity an+1/an tends to 1+O(1/n) which is greater than 1.

I concur.

Who's the spammer now :P I'm concurring with an agreement with my answer :P
52.87   60.07   46.40   72.73   68.23   55.10   98.27   84.73

Offline Haunted

  • Posts Too Much
  • *****
  • Posts: 1378
    • ummm..
Re: Math problem lol
« Reply #9 on: June 09, 2009, 07:32:44 AM »
lol

;D by me ;D


;D Thanks Hlao! ;D


;D Thanks Spood! ;D

Print