title: How to plot figures with different angles in MATLAB
body: <p>I want to plot a curve for different angles </p>
  
  <pre><code>v=10; 
  teta=20; % angle of the projectile motion
  vx=v*cos(teta); % velocity in x axis
  vy=v*sin(teta); % velocity in y axis
  x=0:20;
  y=zeros(size(x));
  
  y=vy.*(x./vx)-(0.5*9.81*(x./vx).^2); % here I calculate the height of the ball in y axis
  plot(x,y)
  set(gca,'ylim',[0,5])
  </code></pre>
  
  <p>How can I change theta in each time to plot theta for 20 and 40 and 60 degrees in same plot ?</p>
  
  <p>Thanks</p>