**CIGAL Reference Manual, Chapter 3 (Functions): atan**
===== Atan -- Calculate the arc tangent of a variable or a ratio =====
**usage:  tgtvarb = atan(srcvarb)**\\
**or:  tgtvarb = atan(svarb1,svarb2)**

The second form calculates the arc tangent of the ratio of the two arguments.
This is done using the C library function ATAN2 instead of ATAN.

**See Also:**\\
[[jvs:cigal|CIGAL Home]], 
[[jvs:cigal:manual|CIGAL Manual]], 
[[jvs:cigal:manual:chapter3|Functions List]], 
[[jvs:cigal:manual:help|Manual Help]]