yahoo ID:matholympaid<br>I'm korea<br>I'd like to share math information with you</font><br><br><br><font color="green"><br>over there .....under.....
2833
matholympaid
Jun 14, 2001 7:12 am
I miss my e-mail~~!!!!<br>jaehoo2@...<br>If you know ,send me...
2834
deeb_george
Jun 14, 2001 3:19 pm
Sorry, it's wrong<br>f'(1-x) is different from f'(x)<br>in fact place this solution, you'l find it wrong...
2835
akinet_01
Jun 14, 2001 4:46 pm
ok this is the problem...I know its very simple but Im not so good at math... <br>The fireworks display for a small community is launched for a platform that...
2836
mathletics
Jun 15, 2001 12:39 am
The height of the rocket at time x seconds is given by: y = -16(squared) + 80x + 20 where y is measured in feet from the ground. <br>When is the height of the...
2837
mathletics
Jun 15, 2001 12:46 am
How about this (I think this is correct)<br><br>ln(y - 1) - ln2 = x + lnx<br>ln(y - 1) = x + lnx + ln2<br>y - 1 = e^(x + lnx + ln2)<br>y - 1 = e^x * e^lnx * ...
2838
adh_math
Jun 15, 2001 2:11 am
weierstrass_99 wrote: "Let A be a set, B be a subset of A, x be an element of A. What's the [sic] necessary and sufficient condition for P(x being element of ...
2839
adh_math
Jun 15, 2001 3:13 am
It seems to me yurt_man's proof starts off okay (provided f is twice-differentiable!) <br>Solving for the constants one easily sees that A=B=0, that is, the...
2840
yurt_man
Jun 15, 2001 9:06 pm
adh_math,<br> you make some good points; I should have been more careful.<br><br> But I do get a non-trivial solution; using your method, I get f(x) = A[cos(x ...
2841
adh_math
Jun 17, 2001 4:23 pm
Oops...right you are! :)<br><br>I dropped a sign in a trig identity when solving for A and B, then didn't do a reality check before posting...<br><br>adh...
2842
jason1990
Jun 18, 2001 6:33 am
Adh is absolutely right. If B is a subest of A, then P(B)=0 is the same as P(B|A)=0 and the conditions for P(B)=0 are purely measure theoretic. Probability and...
2843
weierstrass_99
Jun 18, 2001 7:28 am
Thanks for your help... Well, I was really just wondering if there's any relations A and B should fulfil for P(B|A)=0 from the set theory point of view, those ...
2844
stanislavskyuk
Jun 18, 2001 11:59 am
Just out of interest, can anyone point me anywhere on the web with good information about measure theory - or do I have to buy a text book?...
2845
beata_stehlikova
beata_stehli...
Jun 18, 2001 3:48 pm
Try Probability Tutorial on <a href=http://www.probability.net target=new>http://www.probability.net</a>...
2846
stanislavskyuk
Jun 19, 2001 8:07 am
Thanks! It seems to be mostly theorems and exercises with not much overview, but strangely enough, it gave me a good idea what measure theory is, which is all...
2847
photon256
Jun 19, 2001 9:55 pm
Solve for f(x):<br><br>f(x) * f(1/x) = f(x) + f(1/x)<br><br>f(x) is a polynomial in x<br>f'(3) = 27...
2848
slickcat32
Jun 19, 2001 11:02 pm
Find a rational function that has vertical asymptotes of x=-4 and x=5 and horizontal asymptotes, if any, and oblique asymptotes, if any. (there are many ...
2849
dana_mix
Jun 20, 2001 12:00 am
1/(x^2-x-20) has vertical asymptotes at for x equals -4 and 5. It has horizontal asymtotes at y=0.<br><br>Dana...
2850
slim_the_dude
Jun 20, 2001 2:26 pm
Here is a nonscientific proof. We know f(x) is a polynomial in x. I asked myself what is the order of this polynomial? I started experimenting with orders 0,...
2851
Clooneman
Jun 20, 2001 4:18 pm
Very good, I'm impressed....
2852
yurt_man
Jun 20, 2001 8:36 pm
Let n >= 1 be the degree of f(x).<br> Re-arranging the equaiton, we get<br><br> f(x) f(1/x) - f(x) - f(1/x) + 1<br> = [f(x) - 1][f(1/x) - 1] = 1<br> ==> ...
2853
slim_the_dude
Jun 20, 2001 8:55 pm
Very nice solution, yurt_man. Combining your work with my work, see that 1 + x^3 is the one and only solution. Admittedly, I think the part you proved was ...
2854
yurt_man
Jun 21, 2001 1:47 am
Thanks, slim.<br> I just realized there's a mistake in my proof: From the equation, I should have concluded that f(x) = 1 + cx^k for some c and k. Then, k = n...
2855
photon256
Jun 21, 2001 8:06 pm
Here is another function for you to find:<br><br>f( f(x)-x ) = 2x<br><br>I know the solution:<br>f(x)=2x<br><br>However, I don't know the method to arrive at...
2856
yurt_man
Jun 22, 2001 2:37 pm
This problem is posted in post 151 of the Yahoo! group matholympiad, and solved in post 157, except there, the function takes the positive reals to the ...
2857
photon256
Jun 22, 2001 6:46 pm
Yup, that was the problem. Thanks yurt_man !!...
2858
tdubey2001
Jun 24, 2001 5:48 am
If the constraint that the domain and codomain are both positive reals is not there, f(x)=-x is another solution....
2859
stanislavskyuk
Jun 28, 2001 9:36 am
Can anyone help me?<br><br>I am trying to design a magic trick involving mnemonic techniques and mathematics. A key part of the trick will involve manipulation...
2860
Clooneman
Jun 28, 2001 1:04 pm
Tie one of the digits (not the first or the last) to the last digit of a 6-digit number. Or perform an operation of it. It's a toughie all right....
2861
stanislavskyuk
Jun 28, 2001 1:54 pm
It's not clear to me whether you have understood the problem or not. In either case, perhaps I should add some more detail.<br><br>The problem is, although I...
