Return arc cosine of a number

Contract
Return type	wob
No input parameters.

Water Contract
<method number.integer.acos/>

See also: cos, cosh, sin, asin, sinh, tan, atan, tanh, atan2, radians_to_degrees, degrees_to_radians, integer

Returns the arc cosine of a _subject of type integer . May be used to convert a cosine value back into an angular measure in radians.

-1.<acos />.<radians_to_degrees />

180.0