%
% p.21 2.7�ß �ü�Ï•ª
% –â1

[x,y,z] = meshgrid(-0.1:.3:1.2,-0.1:.3:1.2,-0.1:.3:1.2);
%x=zeros(size(y));
u=zeros(size(x));
v=zeros(size(y));
w=-ones(size(z));
quiver3(x,y,z,u,v,w)
hold on
%surf(x,y,z)

axis([0 1.2 0 1.2 0 1.2])
plot3([0 0],[0 1],[0 1],'r','LineWidth',3)
plot3([0 0],[0 1],[0 0],'m','LineWidth',3)
plot3([0 0],[1 1],[0 1],'m','LineWidth',3)
xlabel('x')
ylabel('y')
zlabel('z')
legend('E','C_1','C_2')