vecrot.m

%VECROT Animation program which shows a rotating vector     -  1
%       defined as a complex number                         -  2
%       This program uses facilities avalable in MATLAB 3.5
%       See Section 4.10 in book.

f = 50;         % frequency, Hz                             -  3
omega = 2*pi*f; % angular frequency, rad/s                  -  4
tmax = 1/50;    % time for a complete rotation, s           -  5
time   = [ ];                                             % -  6
motion = [ ];                                             % -  7
        axis('square')                                    % -  8
        axis([-1 1 -1 1])                                 % -  9
for t = 0: tmax/36: tmax                                  % - 10
        z = exp(i*omega*t);    % complex number description - 11
        x = real(z);           % cartesian projections      - 12
        y = imag(z);                                      % - 13
        time   = [ time t ];                              % - 14
        motion = [ motion y ];                            % - 15
        plot([0, x], [0, y])                              % - 16
        pause(1.0)                                        % - 17
end                                                       % - 18