POV-Ray : Newsgroups : povray.advanced-users : Simple math question : Re: Simple math question Server Time
30 Jul 2024 06:28:46 EDT (-0400)
  Re: Simple math question  
From: Sigmund Kyrre Aas
Date: 23 Dec 1999 15:48:24
Message: <38628A92.374CC2C2@stud.ntnu.no>
Darn. Both are wrong. Setting R=r should be equal to a sphere, but it's
not:
A!=-4*pi*r^2( (sin(1)-pi )
V!=2*pi^2*r^3



Sigmund Kyrre Aas wrote:
> 
> I don't remember that calculus stuff very well, but since no one's
> helped you yet, me and my pocket calculator had a go at it:
> 
> volume:
>   a:=2*int( sqrt(r^2-(x-R)^2) ,x,0,R+r )  // 1/2 torus cross-section
>   int( a*R,theta,0,2*pi )                 // object of revolution
> > R*pi*( pi*r*abs(r)+2*R*sqrt(r^2-R^2)+2*pi*asin(R*abs(1/r))/180*r^2 )
> 
> Odds are this is wrong.. Not sure about line 2.
> 
> area:
>   c:=2*sin(R/r)*r                       // part of arc inside torus
>   int( (2*pi*r-c)*R ,theta,0,2*pi )
> > -4*r*R*pi*(sin(R/r)-pi)
> 
> or something
> 
> sig.
> 
> David Fontaine wrote:
> >
> > What are the equations for surface area and volume of a torus,
> > *including* torii with minor>major radius?
> >
> > --
> > Homepage: http://www.faricy.net/~davidf/
> > ___     ______________________________
> >  | \     |_       <dav### [at] faricynet>
> >  |_/avid |ontaine      <ICQ 55354965>


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