----------------------------------- octopi Sun Dec 07, 2003 10:13 pm f(x) == f(10x) ----------------------------------- 100 bits for someone who solves the following problem: Find a function f(x), where f(x) is equal to f(10x) for all values of x, The varible x must be used in the function. example of how not to do it: f(x) = 4 f(x) can't be 4 (because, the result would be 4 for all values of x), and x is not used in the function. f(x) = 4+x-x NO, because when simplified you get 4, cheap bastards. Good luck. Any cheapory in your anwsers will result in me not giving you bits...aka stupid anwser thats not right. but I didn't cover above in my examples of how not to do it. (like, f(x)= 0x, or f(x)= x^0) ----------------------------------- Mazer Mon Dec 08, 2003 9:16 am Re: f(x) == f(10x) ----------------------------------- f(x)= 0x crap!!! now i have to come up with something else! :evil: ----------------------------------- McKenzie Mon Dec 08, 2003 10:05 am ----------------------------------- int f(int x) { while(x % 10 == 0) x = x / 10; return x; } ----------------------------------- Tony Mon Dec 08, 2003 10:13 am ----------------------------------- :lol: wait :? Is the question about a math function or a programming function :think: btw, McKenzie - since when do you have those billion bits? and for that matter... where did half of my bits go? :think: ----------------------------------- McKenzie Mon Dec 08, 2003 10:36 am ----------------------------------- I think it is supposed to be a math question. I thought a compsci answer was better :wink: bits...what bits? ----------------------------------- Tony Mon Dec 08, 2003 10:41 am ----------------------------------- bits...what bits? :think: umm... can Andy create bits now that he's a mod :think: *Tony takes out his sniper rifle and goes to investigate* :snipe: ----------------------------------- Blade Mon Dec 08, 2003 1:20 pm ----------------------------------- wow, how quickly topics get changed around from the initial equation.. ----------------------------------- Andy Mon Dec 08, 2003 7:29 pm ----------------------------------- f(x)=[1/x] take off the top bar of the square bracket. that is actually a mathematical operator, it means the largest integer smaller than the number contained.... heh that works... but only for integral values of x ----------------------------------- AsianSensation Mon Dec 08, 2003 7:33 pm ----------------------------------- actually that one works for every single number except for 1 itself. [1/1] = 1, [1/10] = 0 ----------------------------------- Andy Mon Dec 08, 2003 7:40 pm ----------------------------------- dope! fine [1/x+1] ----------------------------------- AsianSensation Mon Dec 08, 2003 7:42 pm ----------------------------------- nope, still another fault. [1/(-10 + 1)] = -1, [1/(-1 + 1)] = undefined still not every single number. ----------------------------------- Andy Mon Dec 08, 2003 8:48 pm ----------------------------------- okok i think i actually got it... f(x)=[(x-(|x|/x))/x] how about that? ----------------------------------- Mazer Mon Dec 08, 2003 9:07 pm ----------------------------------- hey dodge, besides the fact that f(x) != f(10x) with your function, what is f(0)? ----------------------------------- Andy Mon Dec 08, 2003 9:20 pm ----------------------------------- yes it does equal... sub in any value... and undefined=undefined rite? ----------------------------------- Mazer Mon Dec 08, 2003 9:41 pm ----------------------------------- uh... as we all know, i really suck at math, so feel free to point out my stupidity if i do something that seems incredibly n00bishly stupid. f(x)= f(5) = (5 - (|5|/5))/5 = (5 - 1) / 5 = 4/5 = 0.8 right? f(50) = (50 - (|50|/50))/50 = (50 - 1)/50 = 49/50 = 0.98 ----------------------------------- Andy Mon Dec 08, 2003 10:30 pm ----------------------------------- f(x)= it was from my previous quote... the [] withought the top bar of the bracket was intended ----------------------------------- rizzix Mon Dec 08, 2003 11:14 pm ----------------------------------- allright i give up.. whats the answer? ----------------------------------- bugzpodder Mon Dec 08, 2003 11:18 pm ----------------------------------- f(x)=|x|/x with f(0) arbitrary or you can obviously define your own functions for example we can make an arbitrary function in the interval [a,10a] where f(a)=f(2a) and then we are define f for all reals by a translation + horizontal stretch by a factor of 10^n ----------------------------------- bugzpodder Mon Dec 08, 2003 11:24 pm ----------------------------------- and since the original question did not specifically state the domain of x, we could let x simply be positive integers and one could use the number theoritical function to obtain f(x)=phi(10x)/x, where phi is defined as Euler's Totient Function http://mathworld.wolfram.com/TotientFunction.html ----------------------------------- PaddyLong Tue Dec 09, 2003 12:08 am ----------------------------------- yes it does equal... sub in any value... and undefined=undefined rite? ... well, isn't that kind of like saying the root of -5 is the same as the root of -1 ? .... ----------------------------------- Andy Tue Dec 09, 2003 11:53 am ----------------------------------- noooo... sqrt(-5)=sqrt(5)i sqrt(-3)=sqrt(3)i ----------------------------------- PaddyLong Tue Dec 09, 2003 11:59 am ----------------------------------- yes, I know... but roots of negative numbers are undefined in the real number system... ----------------------------------- Andy Tue Dec 09, 2003 12:48 pm ----------------------------------- when i said undefined i meant undefined... in all number systems ----------------------------------- PaddyLong Tue Dec 09, 2003 4:11 pm ----------------------------------- kk 8) ----------------------------------- bugzpodder Thu Dec 11, 2003 10:01 am ----------------------------------- so where are my bits? ;)