function area = areaTorus2( t )
% 2.a Computes the cross-sectional area of the torus in 
%     problem 2 for x = t, using the method of shells.
if ( t >= 1 & t <= 3 )
    y = sqrt( 1 - (t-2).^2 ) ;
    height = 2.*y ;
    area = t.*2*pi*height ;
else
    area = 0;
end