It is not indicated whether the returned value shall be in radians or degrees.
Proposed change: Specify the angular units that should returned.
3.17.7.14 [p2544, ATAN]
te
Proposed Disposition of DIS 29500 Comment GB-0375 (Modified: 2007-10-17) The unit of arguments and return values that represent angles is the radian. The formulas having such arguments or return values are ACOS, ASIN, ATAN, ATAN2, COS, SIN, and TAN. This will be made explicit in the descriptions of each of these formulas by the addition of the text ", in radians," or ", in radians", as appropriate, as highlighted in the samples below: 3.17.7.50 COS Syntax: COS ( x ) Arguments: Name Type Description x number The value, in radians, whose cosine is to be determined. 3.17.7.4 ACOS Syntax: ACOS ( x ) Return Type and Value: number The arc cosine of x , in radians . Similar Comments: AU-0025 , CA-0048 , CL-0017 , CL-0018 , CL-0019 , CL-0020 , CL-0021 , CL-0022 , CL-0023 , CL-0159 , CL-0166 , CL-0178 , CL-0182 , CO-0159 , CO-0162 , CO-0163 , CO-0164 , CO-0174 , CO-0201 , CO-0202 , DK-0161 , ECMA-0024 , FR-0440 , FR- 0444 , FR-0445 , FR-0446 , FR-0482 , FR-0490 , FR-0505 , GB-0371 , GB-0374 , GB-0376 , GB-0386 , GB-0424 , GB-0431 , GR-0103 , IE- 0007 , IN-0073 , PH-0002 , US-0173 , US-0176 , US-0177 , US-0178 , US-0185 , US-0220 , US-0227 , UY-0009

Dupe of Ecma 24