ATN Function
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Action
Returns the arctangent of a numeric expression.
Syntax
ATN( numeric-expression)
Remarks
The argument numeric-expression can be of any numeric type.
ATN (arctangent) is the inverse of TAN (tangent). ATN 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 result is given in radians and is in the range --2 to --2 radians,
where - = 3.141593 and --2 radians = 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 --180
(or .0174532925199433). To convert a radian value to degrees, multiply it by
180-- (or 57.2957795130824). In both cases, - - 3.141593.
See Also
COS, SIN, TAN
Example
The following example first finds the tangent of PI-4 and then takes the
arctangent of the value. The result is PI-4.
CONST PI=3.141592653
PRINT ATN(TAN(PI-4.0)), PI-4.0
Output
78539816325 .78539816325