title: Angle in 360 degrees
body: <p>I coded this code here:</p>
  
  <pre><code>     double cosine = (v1.x*v2.x+v1.y*v2.y)/(150*150);               
       double radian = Math.acos(cosine);
       double angle = Math.toDegrees(radian);
  </code></pre>
  
  <p>V1 and V2 are two vectors, which are simple Point(s)() to keep it simple. Now I calc. the angle between them and it works well. But over 180 deg. , it turns back to 179,178... But I want to have 360°. </p>
  
  <p>The Problem is that for example radian won't get negative, so that I'm able to put it in an if-Segment...</p>
  
  <p>Thanks for advice.</p>