Check the following. Also, check the range of theta_1 and (r2v or r3v). If you try to plot these three in a graph you can't see r2v and r3v that much; since it have range much lesser than theta_1. Therefore I did in separate plots.
samples = (1:100)';
theta_1 = 0 + (90)*rand(100,1);
r2v = 0 + (0.5)*rand(100,1);
r3v = 0 + (0.5)*rand(100,1);
figure;
plot(samples, theta_1,'.r'); % Check the Y scale of fig1 and fig 2
figure; hold on;
plot (samples, r2v, '.b');
plot (samples, r3v, '.g' );
figure
[hAx,hLine1,hLine2] = plotyy(samples,theta_1, [samples',samples'], [r2v',r3v']);
set(hLine1,'LineStyle','--')
set(hLine2,'LineStyle',':')
