xlist = linspace ( -0.5, 1.5, 101 );
ylist1 = 4*xlist-3;
ylist2 = 4*xlist.^2-3;
plot ( xlist, ylist1, 'r-', ...
       xlist, ylist2, 'g-', ...
       xlist, 0*ylist, 'k:', ...
       [0.0, 0.0], [ 0.0, -3.0], 'b-', ...
       [1.0, 1.0], [ 0.0,  1.0], 'b-', ...
       0.0, -3.0, 'b.', ...
       1.0,  1.0, 'b.', ...
       0.75, 0, 'r.', ...
       0.866, 0, 'g.', ...
       0.5, 0, 'k.',...
       'Linewidth', 3, 'Markersize', 50 );
grid on
xlabel ( '<-- X -->' )
ylabel ( '<-- Y -->' );
title ( 'Compare bisection.', 'Fontsize', 24 );
print ( '-djpeg', 'secant_ill4.jpg' );
axis ( [ -0.5, 1.5, -5, 3] )

