title: Why are there no asin2() and acos2() functions similar to atan2()?
body: <p>From my understanding, the <code>atan2()</code> function exists in programming languages because <code>atan()</code> itself cannot always determine the correct theta since the output is restricted to -pi/2 to pi/2. </p>
  
  <p>If this is the case, then the same problem applies to both <code>asin()</code> and <code>acos()</code>, both of whom also have restricted ranges, so then why are there no <code>asin2()</code> and <code>acos2()</code> functions?</p>