For the trigonometric functions, SIN (Part 4, Section 3.17.7.287), COS (Part 4, Section 3.17.7.50) and TAN (Part 4, Section 3.17.7.313), the specification fails to state whether their arguments should express angles in radians or degrees. A similar problem exists for the return value of the inverse functions, ASIN (Part 4, Section 3.17.7.12), ACOS (Part 4, Section 3.17.7.4), ATAN (Part 4, Section 3.17.7.14), and ATAN2 (Part 4, Section 3.17.7.15).
The specification should be changed to declare the use of radians for arguments to these functions.
Part 4, Section 3.17.7
ed
Proposed Disposition of DIS 29500 Comment IE-0007 (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-0375 , GB-0376 , GB-0386 , GB-0424 , GB-0431 , GR-0103 , IN-0073 , PH-0002 , US-0173 , US-0176 , US-0177 , US-0178 , US-0185 , US-0220 , US-0227 , UY-0009

Dupe of Ecma 27