----------------------------------- Mazer Tue Jul 22, 2003 3:10 pm math thread number 3,141,592,653 ----------------------------------- just some random question: Imagine a circle of radius 10 units centered at the origin. Now rotate the circle about the x-axis to create a sphere. Where would you need to place vertical planes in order to divide the volume of the sphere into three sections of equal volume? the the first person to not give a COMPLETE SOLUTION to this problem you will win everyone's favourite currency... bits! (actual number of bits rewarded will be determined at a later date by yet another mathematic solution.) don't waste time reading this text! go solve that problem and tell me your answer... if you dare! ----------------------------------- bugzpodder Tue Jul 22, 2003 5:21 pm ----------------------------------- w00t?! :shock: to not give a COMPLETE SOLUTION to this problem not give a complete solution? ok, i will just give an answer. z=2.3 and z=-2.3 you had to know a bit of calculus... but... ----------------------------------- Mazer Wed Jul 23, 2003 9:03 am ----------------------------------- yay! you didn't give a complete solution! hmm... how many bits do i have? ----------------------------------- bugzpodder Wed Jul 23, 2003 9:26 am ----------------------------------- heh... am i right? ----------------------------------- Mazer Wed Jul 23, 2003 11:38 am ----------------------------------- :P i forgot to check the answer on the site. i think it was something like that though. ----------------------------------- bugzpodder Wed Jul 23, 2003 12:03 pm ----------------------------------- you have 4 bits now ;) ----------------------------------- Mazer Wed Jul 23, 2003 1:46 pm ----------------------------------- yeah... that's kind of annoying... ah well i'll let them build up again and give them away ----------------------------------- krishon Sun Jul 27, 2003 4:56 pm ----------------------------------- lol ----------------------------------- AsianSensation Sun Jul 27, 2003 10:01 pm ----------------------------------- bugz, can you show the full solution though? And could you explain the calculus part a bit more please? ----------------------------------- SilverSprite Sun Jul 27, 2003 10:27 pm ----------------------------------- ok why dont you go learn some calculus for yourself and write this question down. and then you can come back and ask questions if you still don tknow. you cant ask someone to practically teach you the calculus and then show you how to do the question... i dunno maybe bugz wants to show you .. up to him ----------------------------------- AsianSensation Sun Jul 27, 2003 10:44 pm ----------------------------------- know a place where there is a good calculus tutorial? or you'll let me borrow a book? I want to learn calculus, but can't find a place to start, and can't seem to find proper sources to teach me. ----------------------------------- bugzpodder Sun Jul 27, 2003 11:01 pm ----------------------------------- i want to calculate the volume of a surface of revolution, which is given by the integral of pi*(f(x))^2 we can exploit the symmetry of the sphere by integrating and equating: Int {-2pi to -a} pi*(100-x^2)=Int {-a to a} pi*(100-x^2) you will then get a cubic equation and you can either use cubic formula, newton's method of approximating roots, or simply use a graphing calculator or something along the lines. ----------------------------------- SilverSprite Mon Jul 28, 2003 4:59 pm ----------------------------------- i want to calculate the volume of a surface of revolution, which is given by the integral of pi*(f(x))^2 we can exploit the symmetry of the sphere by integrating and equating: Int {-2pi to -a} pi*(100-x^2)=Int {-a to a} pi*(100-x^2) you will then get a cubic equation and you can either use cubic formula, newton's method of approximating roots, or simply use a graphing calculator or something along the lines. :shock: ugh... i got all that :roll: 8) lol