==============================================================================
	areaShell.m 
==============================================================================
%
% Computes the area of the shell taken by cutting the torus given by
%    (x - 2)^2 + y^2 = 1
% parallel to the y-axis at x.
%
function a = areaShell(x)

% Area of the shell at x is 2*pi*x*ht(x)  
% where ht(x) is the height of the shell at x

height = 2*sqrt(1 - (x - 2).^2);
a = 2*pi*x.*height;


==============================================================================
	volumeTorus.m 
==============================================================================
%
% Computes the volume of the solid obtained by cutting the torus along
% the x-axis at t.
%
function vol = volumeTorus(t)

vol = quad('areaShell', 1, t);


==============================================================================
	volLess20.m 
==============================================================================
%
% Computes (the volume of the solid obtained by cutting the torus along
% the x-axis at t ) - 20
%
% It's necessary to do this to use the function with Matlab's fzero 
% function (which assumes equations are set up in standard form: 
% f(x) = 0).
%
function vol = volLess20(t)

vol = volumeTorus(t) - 20;