phi_fine = 0:pi/20:2*pi; % For drawing accurately.
r = 1;
[x_fine, y_fine] = pol2cart(phi_fine, r); 
plot(x_fine,y_fine,'-k') % Plot unit circle.
hold on

phi = 0:pi/2:2*pi; % For plotting vectors.
phi = phi  + pi/8; % Offset vector positions.

[x,y] = pol2cart(phi, r)
plot(x,y, 'o') % Plot vector positions.
plot(0,0,'o') % Plot origo.

% r unit vector
U = cos(phi); % x-component. 
V = sin(phi); % y-component.
quiver(x,y,U,V);

% phi unit vector
U = -sin(phi) % x-component. 
V = cos(phi)  % y-component. 
quiver(x,y,U,V)

axis square
grid on