Author 
Message 
Mazer

Posted: Tue Jul 22, 2003 3:10 pm Post subject: math thread number 3,141,592,653 


just some random question:
Quote:
Imagine a circle of radius 10 units centered at the origin. Now rotate the circle about the xaxis 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! 





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bugzpodder

Posted: Tue Jul 22, 2003 5:21 pm Post subject: (No subject) 


w00t?!
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

Posted: Wed Jul 23, 2003 9:03 am Post subject: (No subject) 


yay! you didn't give a complete solution!
hmm... how many bits do i have? 





bugzpodder

Posted: Wed Jul 23, 2003 9:26 am Post subject: (No subject) 


heh... am i right? 





Mazer

Posted: Wed Jul 23, 2003 11:38 am Post subject: (No subject) 


i forgot to check the answer on the site. i think it was something like that though. 





bugzpodder

Posted: Wed Jul 23, 2003 12:03 pm Post subject: (No subject) 


you have 4 bits now 





Mazer

Posted: Wed Jul 23, 2003 1:46 pm Post subject: (No subject) 


yeah... that's kind of annoying... ah well i'll let them build up again and give them away 





krishon

Posted: Sun Jul 27, 2003 4:56 pm Post subject: (No subject) 


lol 





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AsianSensation

Posted: Sun Jul 27, 2003 10:01 pm Post subject: (No subject) 


bugz, can you show the full solution though? And could you explain the calculus part a bit more please? 





SilverSprite

Posted: Sun Jul 27, 2003 10:27 pm Post subject: (No subject) 


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

Posted: Sun Jul 27, 2003 10:44 pm Post subject: (No subject) 


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

Posted: Sun Jul 27, 2003 11:01 pm Post subject: (No subject) 


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*(100x^2)=Int {a to a} pi*(100x^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

Posted: Mon Jul 28, 2003 4:59 pm Post subject: (No subject) 


bugzpodder wrote: 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*(100x^2)=Int {a to a} pi*(100x^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.
ugh... i got all that 8) lol 





