return square root of an integer

Contract
Return type	wob
No input parameters.

Water Contract
<method number.integer.sqrt/>

See also: sqrt, is_nan

Returns the square root of a _subject of type integer as a double .

169.<sqrt />

13.0

34862.<sqrt />

186.71368455472137

If the _subject is negative, sqrt returns a value of NaN (not a number).

-144.<sqrt />.<is_nan />

true