title: Java: Tangent method
body: <p>What is the opposite of the <code>Math.tan(double x)</code> function of java?  </p>
  
  <p>I know that <code>Tan(X) = oppositeSideLength/AdjacentSideLength</code> </p>
  
  <p>but I have the opposite and adjacent sides so I want to do the opposite operation.  </p>
  
  <p>ie: <code>x = Tan^-1(oppositeSideLenght/AdjacentSideLength)</code> (that is how I would enter it in a calculator.  </p>
  
  <p>I just looked in the <a href="http://download.oracle.com/docs/cd/E17476_01/javase/1.4.2/docs/api/java/lang/Math.html" rel="nofollow noreferrer">Math class</a> and I know that there is: </p>
  
  <ul>
  <li><code>Math.atan(</code></li>
  <li><code>Math.atan2</code></li>
  </ul>
  
  <p>but I don't think that either of these is what I am looking for.  </p>