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Messages 12708 - 12738 of 13927   Oldest  |  < Older  |  Newer >  |  Newest
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12708
One way of counting the number of ways of making change is first to define: F(k) = floor(k/2)+1 which for k=0,1,2,3,..., is 1,1,2,2,3,3,4,4,... and which is...
video_ranger
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Jun 2, 2007
1:12 am
12709
... and ... of ... = ... I agree. I meant finding a solution is easy. I don't know why this is the only solution. Of course, this is Sloane sequence A000008. I...
cooperpuzzles
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Jun 5, 2007
9:34 am
12710
Gentlemen: I found this problem in a math site (Certamen el Numero de Oro 1998) and I have been unable to find its solution. Would some one of you, members of...
lbitran
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Jun 12, 2007
3:06 pm
12711
... 1998) ... Counterexample: n = 1 Then N = 2 - 1 = 1 Oops. 1 is a perfect cube....
slim_the_dude
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Jun 13, 2007
1:23 am
12712
... you, ... p2, ... O.K. Fine. But I forgot to say: n>1...
lbitran
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Jun 13, 2007
2:13 am
12713
Try this: 3 | k^3+1 <=> 3 | (k+1)*(k^2 - k + 1) 3 | (k+1) <=> 3|(k^2 - k + 1) (check e.g. by checking congruence modulo 3) thus: 3 | k^3 + 1 => 3^2 | k^3 + 1 ...
minthem
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Jun 13, 2007
10:13 am
12714
... k can take 3 forms: 3m,3m+1,3m+2. (3m)^3 + 1 = 27m^3 + 1. This is not div by 3. (3m+1)^3 + 1 = 27m^3+27m^2+9m+1 + 1. This is not divisible by 3. ...
cino hilliard
hillcino368
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Jun 13, 2007
12:28 pm
12715
... 9. then ... impossible. ... A fine solution. Thank you very much, lbitran...
lbitran
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Jun 13, 2007
4:05 pm
12716
... 9. then ... impossible. ... Very clever and interesting. But what is special about 3? Could this type of proof be done with another number, say, 5? ...
cooperpuzzles
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Jun 14, 2007
6:51 am
12717
... Well it is proved that if P(n) = the product of the first n primes then P(n)-1 can not be a cube for n > 1. The question to ask is can this type of proof...
ramsey2879
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Jun 14, 2007
5:07 pm
12718
... of ... proof. ... 2,3,4 ... expansion ... coeficient C ... Two observations: (a)When you extend the argument to proof that p(n)-1 can not be a 5th, 7th,...
lbitran
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Jun 16, 2007
10:40 pm
12719
... by ... Not exactly. However, the concept of divisibility can be generalized. Using the "forms" notation (which I prefer to the modulo) a number k is of the...
Cino Hilliard
hillcino368
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Jun 17, 2007
7:26 am
12720
... But the proof depends upon P(n) being divisible by the 1st power of the nth prime but not the square of the nth prime. P(k) is not divisible by the nth...
ramsey2879
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Jun 18, 2007
5:35 pm
12721
... 3. ... divisible ... is ... of ... proof. ... generalized. ... k ... coefficients ... The original question can be generalized. Your proof works when N + 1...
cooperpuzzles
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Jun 21, 2007
5:45 pm
12722
Here is a question someone posted on Yahoo Answers which I think never got fully resolved. Suppose we shuffle a standard deck of cards. What are the...
jwwarrenva
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Jun 26, 2007
12:40 am
12723
jwwarrenva <no_reply@yahoogroups.com> wrote: Here is a question someone posted on Yahoo Answers which I think never got fully resolved. Suppose we...
mohanad masri
modalmasri
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Jun 26, 2007
3:05 pm
12724
Can you help me to find out how to calculate (create a formula)the summary 1(1!)+2(2!)+3(3!)+4(4!)+...+n(n!)? Thanks (and if you can I would appreciate if you...
grchrysos
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Jun 27, 2007
12:12 pm
12725
... summary ... Note that n(n!)=(n+1)(n!)-n! Your series then becomes (2!-1!)+(3!-2!)+(4!-3!)+...+((n+1)!-n!) =(n+1)!-1! =(n+1)!-1 HM...
teohhockmeng
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Jun 27, 2007
1:59 pm
12726
... question someone posted on Yahoo Answers which I think never ... rank ... total number of cards is ... the cards on the rank ... second card ... story. ......
video_ranger
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Jun 27, 2007
3:51 pm
12727
It looks so interesting - does anyone use this educational game math cd? go to this website http://www.marthamaths.com/product.html...
hanazku
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Jun 28, 2007
12:42 am
12728
... question someone posted on Yahoo Answers which I think never ... total number of cards is ... the cards on the rank ... second card ... Mohanad, I've tried...
jwwarrenva
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Jun 28, 2007
12:43 am
12730
Take a look at http://www.usaone.net/jokenet/jokes.asp?command=list&r=108 Maybe someone here would like to prove number 3. Have fun, Cino...
cino hilliard
hillcino368
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Jul 1, 2007
12:29 am
12731
... There are 293 ways to make change for a dollar, but only if you include a silver dollar among your coins. Here is a generatingfunctionological approach. ...
jwwarrenva
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Jul 1, 2007
11:52 am
12732
Studies show goldfish have memories of more than 3 seconds. The speaker of the house can speak. He can't take sides in a debate, he effectively chairs the...
Dora
lovetostitch...
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Jul 1, 2007
7:47 pm
12733
For A + B + C = 360 degrees Prove that [sin(A) + sin(B) + sin(C)] is maximum when A = B = C I kind of see a pattern on excel in favor the proof but just...
Daniel
kkjb1999
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Jul 1, 2007
8:56 pm
12734
Hello Positive and informative responses in my first question 6 years ago http://tech.groups.yahoo.com/group/mathforfun/messages/3391?threaded=1&m\ ...
ynineteen
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Jul 2, 2007
2:43 am
12735
Hello Positive and informative responses in my first question 6 years ago encouraged me to post my second puzzle in this forum that its membership with...
ynineteen
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Jul 2, 2007
2:48 am
12736
During a workout a runner starts on a flat surface and runs at 8 mph. She then goes up a hill at 6 mph. She turns around and retraces her route going 12 mph...
cooperpuzzles
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Jul 2, 2007
3:32 pm
12737
Since the distance uphill and downhill are equal, and they average 8 mph, it would be the same as running 2 hours at 6mph. Therefore the total distance is 12...
Tarcisio Goes
tarcisiogoes
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Jul 2, 2007
3:48 pm
12738
... wondering if ... Except for a factor (1/2) this is the area of the triangle formed by three points on a unit circle where A,B,C are the arc angles between ...
video_ranger
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Jul 2, 2007
4:46 pm
Messages 12708 - 12738 of 13927   Oldest  |  < Older  |  Newer >  |  Newest
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