UPSB v4

Off-topic / Math Problem

  1. cl3ud.kr
    Date: Sun, Oct 12 2014 02:55:47

    halp me nao

  2. Monk
    Date: Sun, Oct 12 2014 03:51:01

    cl3ud.kr wrote: halp me nao http://i.imgur.com/nrQYoUm.png
    give up

  3. casual
    Date: Sun, Oct 12 2014 04:01:26

    http://en.wikipedia.org/wiki/Geometric_series

  4. ShadowParadox
    Date: Sun, Oct 12 2014 05:19:52

    What's the question? Nth term?

  5. Walkaz
    Date: Sun, Oct 12 2014 06:26:12

    @casual doesnt look like a geometric progression imo

  6. casual
    Date: Sun, Oct 12 2014 06:37:36

    Walkaz wrote: @casual doesnt look like a geometric progression imo
    Ah my bad you're right the "constant term" isn't constant. http://en.wikipedia.org/wiki/Summation Seems like the formula for that summation is on this page.

  7. Soren
    Date: Sun, Oct 12 2014 09:43:14

    47

  8. x1213
    Date: Sun, Oct 12 2014 10:10:58

    Let s = 1/2 + 1/4 + 1/8 + ... It is not hard to observe that s = 1. 1 x 1/2 + 2 x 1/4 +3 x 1/8 + ... = s + (1 x 1/4 + 2 x 1/8 + 3 x 1/16 + ...) = s + 1/2 x s + (1 x 1/8 + 2 x 1/16 + 3 x 1/32 + ...) = s + 1/2 x s + 1/4 x s + 1/8 x s + ... = (1 + 1/2 + 1/4 + 1/8 + ...) x s = 2s x s = 2

  9. Ceru Seiyu
    Date: Sun, Oct 12 2014 11:52:25

    x1213 wrote: Let s = 1/2 + 1/4 + 1/8 + ... It is not hard to observe that s = 1. 1 x 1/2 + 2 x 1/4 +3 x 1/8 + ... = s + (1 x 1/4 + 2 x 1/8 + 3 x 1/16 + ...) = s + 1/2 x s + (1 x 1/8 + 2 x 1/16 + 3 x 1/32 + ...) = s + 1/2 x s + 1/4 x s + 1/8 x s + ... = (1 + 1/2 + 1/4 + 1/8 + ...) x s = 2s x s = 2
    Oh god how did I not see this.

  10. cl3ud.kr
    Date: Sun, Oct 12 2014 15:34:27

    lmao wait can i kill myself like now i knew all along that if s is 1/2 + 1/4 + 1/8 ... then s = 1, but i had no goddamn idea how to use it :<<<

  11. kvanimation
    Date: Sun, Oct 12 2014 20:45:04

    of course it took an asian to solve this