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Topic review (newest first)
- krassi_holmz
- 2005-12-05 17:09:52
Ganesh,
I think c) proof isn't very right. Because you have "let" here. Here's a proof without "let":
(b means black, w means white)
Let...
b1+w1=b2
b2+w2=b3
so
b1+w1+w2=b3; b1+(w1+w2)=b3,
but
b1+w3=b3, so w1+w2=w3.
- Ricky
- 2005-12-05 08:17:00
Draw the triangle, and then draw it again rotated so that B is in the same corner that C was. Now since ICA < IBA and ICB < IBC, ICA + ICB < IBA + IBC. Since this is true, the angle at C is less than the angle at B. I forget the name of the proof, but if you have such a triangle, the side with a greater angle has a smaller diagonal (BB' and CC'). So Since angle C < B, CC' > BB'.
I don't understand quite understand the wording in 2.
- math
- 2005-10-31 19:48:52
the problem were unsolve in along time ago !!!!!!!!!
- math
- 2005-10-30 18:27:00
- math
- 2005-10-27 08:41:27
next week , i will give the proof to my teacher ,please , !!!!!!!
- math
- 2005-10-25 21:40:33
very thanks to ganesh !!!! 
- ganesh
- 2005-10-25 14:13:22
math wrote:
C)in assemble N ,every number is white or black so that white + black=black
prove : white + white = white
Let white=0, black=1;
white + black = 0 + 1 = 1 = black
white + white = 0 + 0 = 0 = white, Proved!
For A), B) please give some time. Yes, Proofs aren't too easy. They are time consuming.
- math
- 2005-10-24 22:09:08
- MathsIsFun
- 2005-10-24 07:39:56
Maybe ganesh could post these one at a time under "Ganesh's Puzzles".
- Flowers4Carlos
- 2005-10-24 07:10:12
never fear!!! Flowers4Carlos is here to save the day!!!!
*looks at the problem*
eeeeek..... *falls down*
- math
- 2005-10-24 02:32:50
nobody
- math
- 2005-10-20 21:56:06
thanks . I will be waiting for you
- MathsIsFun
- 2005-10-20 16:09:16
Yes, that's right ... I said it wasn't really a proof.
I am sorry, but your questions are difficult, I am just hoping someone can spare the time to work on answer for you. I have unfortunately been a little busy recently.
- math
- 2005-10-20 13:09:34
your proff is wrong . please help me in problem B,C
- MathsIsFun
- 2005-10-18 23:11:01
No, not yet. Proofs are very difficult.
Ideas are easy, though. For "C" I can think of:
white + black=black
therefore: black-black=white, but black-black=0
therefore: white+white = 0 + 0 = 0 = white
But this is not really a proof