plotDecisionBoundary.m

function plotDecisionBoundary(theta, X, y)
plotData(X(:,2:3), y);
hold on
plot_x = [min(X(:,2)),  max(X(:,2))];
plot_y = (-1./theta(3)).*(theta(2).*plot_x + theta(1));
plot(plot_x, plot_y)
legend('Metal', 'Classical', 'Decision Boundary')
axis([-26, -12, 0, 25])
end