title: Comparing two Vector Direction MATLAB
body: <p>I have three vessels and the direction of these vessels is given by <code>V1</code>, <code>V2</code> and <code>V3</code>:</p>
  
  <pre><code>V1 = [0.7030  -0.7112]
  V2 = [0.5099  -0.8602]
  V3 = [-0.6799  -0.7333]
  </code></pre>
  
  <p>And here's their graphical visualization:</p>
  
  <p><img src="https://i.stack.imgur.com/ldBDZ.png" alt="vectors"></p>
  
  <p>How can I find if <code>V3</code> is "approaching" <code>V2</code> (as shown in the figure) or "leaving" <code>V2</code>? I want to check if vessel #3 is part of vessel #1 or vessel #2, <em>i.e</em> if vessel #3 is branching from vessel #1 then <code>V3</code> is "away" from <code>V1</code> and "towards" <code>V2</code> (shown in figure) and in that case vessel #3 is part of vessel #1.</p>
  
  <p>How do I do this in MATLAB?</p>