Please turn on javascript in your browser to play chess.
Posers and Puzzles

Posers and Puzzles

  1. Subscriber AThousandYoung
    It's about respect
    18 Oct '04 20:34
  2. Subscriber Brother Edwin
    7 edits
    21 Oct '04 16:09
    4+4=8.

    Then swap the 4 for a 3.
  3. Subscriber AThousandYoung
    It's about respect
    22 Oct '04 04:20
    Nope.
  4. Standard member TheMaster37
    Kupikupopo!
    22 Oct '04 09:23
    Using axioms of mathematics;

    3+4 = 4+3 this is the communitative property of addition.
    4+3 = 4+(2+1) this is the definition of 3
    4+(2+1) = 4+(1+2)
    4+(1+2) = (4+1) +2 this is the associative property of addition
    (4+1) +2 = 5+2 this is the definition of 5
    5+2 = 5+(1+1) this is the definition of 2
    5+(1+1) = (5+1) +1
    (5+1) +1 = 6+1 this is the definition of 6
    6+1 = 7 this is the definition of 7

    Proof above shows 3+4=7, nothing more, nothing less.

    Now by assuming 0=1 or some other equivalent statement, it's easy to show 7=8, making 3+4=7=8. Alas, 3+4 would equal anything then.
  5. Subscriber AThousandYoung
    It's about respect
    22 Oct '04 23:53
    I still say 3 + 4 = 8, and I can prove it.
  6. Standard member XanthosNZ
    Cancerous Bus Crash
    23 Oct '04 02:33
    (3^2) - 21 = (4^2) - 28
    9 - 21 + (35/4) = 16 - 28 + (35/4) Adding 35/4 to both sides
    (3 - (7/2))*(3- (7/2)) = (4 - (7/2))*(4 - (7/2)) Factorising
    (3 - (7/2)) = (4 - (7/2) Taking the square root of both sides
    Therefore 3 = 4

    Substituting into the equation 4 + 4 = 8
    we get 4 + 3 = 8

    How's that?
  7. 23 Oct '04 07:11
    gj Brother Edwin ur my hero ^.^
  8. Standard member Ragnorak
    For RHP addons...
    23 Oct '04 14:30 / 1 edit
    Originally posted by XanthosNZ
    (3^2) - 21 = (4^2) - 28
    9 - 21 + (35/4) = 16 - 28 + (35/4) Adding 35/4 to both sides
    (3 - (7/2))*(3- (7/2)) = (4 - (7/2))*(4 - (7/2)) Factorising
    (3 - (7/2)) = (4 - (7/2) Taking the square root of both sides
    Therefore 3 = 4

    Substit ...[text shortened]... ting into the equation 4 + 4 = 8
    we get 4 + 3 = 8

    How's that?
    so that means that 3 + 3 = 8 as well??? And inversely, 4 + 4 = 6???

    D
  9. Standard member TheMaster37
    Kupikupopo!
    23 Oct '04 15:03
    lets write 3-7/2 differently; -1/2

    Name 1/2 = a. So 3-7/2 = -a

    (-a)^2 = a^2

    taking roots; -a = a

    Mind your math people!
  10. Standard member telerion
    True X X Xian
    23 Oct '04 16:29 / 1 edit
    Originally posted by XanthosNZ
    (3^2) - 21 = (4^2) - 28
    9 - 21 + (35/4) = 16 - 28 + (35/4) Adding 35/4 to both sides
    (3 - (7/2))*(3- (7/2)) = (4 - (7/2))*(4 - (7/2)) Factorising
    (3 - (7/2)) = (4 - (7/2) Taking the square root of both sides
    Therefore 3 = 4

    Substit ...[text shortened]... ting into the equation 4 + 4 = 8
    we get 4 + 3 = 8

    How's that?
    9 - 21 + (35/4) = 16 - 28 + (35/4) Adding 35/4 to both sides

    (3 - (7/2))*(3- (7/2)) = (4 - (7/2))*(4 - (7/2)) Factorising


    Uhm . . . you also have an arithmetic error.

    (-7/2)*(-7/2) = 49/4

    ok let's say you changed 35/4 to 49/4

    you basically have (-1/2)*(-1/2) = (1/2)*(1/2) True.

    but the next line is equivalent to -1/2 = 1/2 False.

    Problem? sqrt(1/4) = 1/2 or -1/2
    From this however we cannot say that 1/2 = -1/2





  11. Standard member genius
    Wayward Soul
    23 Oct '04 17:44
    Originally posted by TheMaster37
    Mind your math people!
    so, are you saying you can prove it without making any mathematical mistakes...?

    how about prove 0.9 rec=1?
  12. Standard member XanthosNZ
    Cancerous Bus Crash
    23 Oct '04 21:47
    (-7/2)*(-7/2) = 49/4
    ok let's say you changed 35/4 to 49/4
    you basically have (-1/2)*(-1/2) = (1/2)*(1/2) True.
    but the next line is equivalent to -1/2 = 1/2 False.
    Problem? sqrt(1/4) = 1/2 or -1/2
    From this however we cannot say that 1/2 = -1/2
    Yes you're right. It seems I can't multiply. You are also right in finding the flaw in the logic of my argument. Of course it's there. You don't actually think I can prove 3=4 without one do you? There is the more common 'proof' of 1=2 that uses dividing by zero.
    Nice eyes spotting the mistake though. First time round it took me a while.
  13. Standard member telerion
    True X X Xian
    23 Oct '04 22:37
    Originally posted by XanthosNZ
    Yes you're right. It seems I can't multiply. You are also right in finding the flaw in the logic of my argument. Of course it's there. You don't actually think I can prove 3=4 without one do you? There is the more common 'proof' of 1=2 that uses dividing by zero.
    Nice eyes spotting the mistake though. First time round it took me a while.
    Certainly, I didn't expect you to actually believe your proof. Good job thinking up the completing the square bit.
  14. Standard member XanthosNZ
    Cancerous Bus Crash
    24 Oct '04 01:37 / 1 edit
    I can't take full credit. It was first shown it by a math teacher years ago.
  15. Subscriber AThousandYoung
    It's about respect
    25 Oct '04 00:16 / 1 edit
    Wow Xanthos, that's pretty amazing. It's not the answer I was thinking of though.

    how about prove 0.9 rec=1?

    I already did this one on the other thread.