**CIGAL Reference Manual, Chapter 3 (Functions): acos**
===== Acos -- Calculate the arc-cosine of a variable =====
**usage: result = acos(x)**

The ACOS function returns the arccosine of its argument.  The input value must
be in the range -1 to 1, and the output will be in the range 0 to 180 (degrees);
illegal input values result in an output value of -1.  If the input X is a
variable with more than one value, ACOS will generate an output variable with
the same number of values.

**See Also:**\\
[[jvs:cigal:manual:chapter3:asin|ASIN(3)]], 
[[jvs:cigal:manual:chapter3:cos|COS(3)]], 
[[jvs:cigal:manual:chapter3:sin|SIN(3)]]

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