title: Finding Inverse Cosine in Radians
body: <p>This gives me the answer in degrees but I want the answer in Radians for Inverse Cosine. 
  For example if I pick 0.5 for invCosineVal it will return 60 deg but not sure how I can find the answer in Radians which should be 1.047.</p>
  
  <pre><code>ans = Math.acos(invCosineVal) * (180/Math.PI);
  </code></pre>