%
% 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 getToZero = volLess20(t)

getToZero = volumeTorus(t) - 20;