◄Syntax► ◄Details► ◄Example► ◄Contents► ◄Index► ◄Back► ────────────────────────────────────────────────────────────────────────────── ATN returns the arctangent of a numeric expression. ATN(numeric-expression) ■ The argument numeric-expression can be of any numeric type. Usage Notes ■ ATN (arctangent) is the inverse of tangent (TAN) and takes the ratio of two sides of a right triangle (numeric-expression) and returns the corresponding angle. The ratio is the ratio of the lengths of the side opposite the angle and the side adjacent to the angle. ■ The arctangent is given in radians and is in the range -PI/2 to PI/2 radians, where PI = 3.141593 and PI/2 radians equals 90 degrees. ■ ATN is calculated in single precision if numeric-expression is an integer or single-precision value. If you use any other numeric data type, ATN is calculated in double-precision. ■ To convert values from degrees to radians, multiply the angle (in degrees) times PI/180 (or .0174532925199433) where PI = 3.141593. ■ To convert a radian value to degrees, multiply it by 180/PI (or 57.2957795130824) where PI = 3.141593.