Return cosine of a number

Contract
Return type	wob
No input parameters.

Water Contract
<method number.double.cos/>

See also: acos, cosh, sin, asin, sinh, tan, atan, tanh, atan2, radians_to_degrees, degrees_to_radians, double

Returns the cosine of a _subject of type double .

45.<degrees_to_radians />.<cos />

0.7071067811865476