title: How should I tackle ARCTAN (and prevent deviding by zero) without the convenience of ARCTAN2(n,m) being available?
body: <p>I try to determine the angle from a point <code>(n,m)</code> to <code>(0,0)</code>. Without <code>arctan2</code> being available, I'm running into the problem that <code>m</code> can be 0, which leads to a possible division by zero.</p>
  
  <p>What would be an elegant, correct solution to tackling this issue?</p>