Returns the arc cosine of the argument, the result being in the range zero to
acos($arg as xs:double?) ➔ xs:double?
The supplied angle in radians
Links to W3C specifications
XPath 3.1 Functions and Operators
Available in XPath 3.0, XSLT 3.0, XQuery 3.0, and later versions. From Saxon 9.6, available in all editions.
Notes on the Saxon implementation
Implemented since Saxon 9.3; available whether or not support for XPath 3.0 is enabled.
Saxon also (for compatibility) implements the function math:acos() in namespace