2.13.1. ProblemYou have numbers in degrees but want to use the trigonometric functions. 2.13.2. SolutionUse deg2rad( ) and rad2deg( ) on your input and output: $cosine = cos(deg2rad($degree)); 2.13.3. DiscussionBy definition, 360 degrees is equal to 2Π radians, so it's easy to manually convert between the two formats. However, these functions use PHP's internal value of Π, so you're assured a high-precision answer. To access this number for other calculations, use the constant M_PI, which is 3.14159265358979323846. There is no built-in support for radians. This is considered a feature, not a bug. 2.13.4. See AlsoRecipe 2.12 for trig basics; documentation on deg2rad( ) at http://www.php.net/deg2rad and rad2deg( ) at http://www.php.net/rad2deg . |