Purpose
Returns the arc tangent of an arithmetic expression.
Parameters
x and y are floating-point values such that y is not zero, or are expressions that can be converted to such values.
Examples
X = 3.14157;
Y = 2.0;
RADIANS = ATAN(X); /* 1.26 */
or
RADIANS ATAN(X,Y); /* 1.00 */
Restrictions
An ATAN operation on Float Decimal data is actually performed using its Float Binary equivalent. Thus, the ranges of the operands and the result are limited to the range of Float Binary data.
Description
ATAN(x) returns the arc tangent of x. The result is such that -Π/2 ≤ ATAN(x) ≤ Π/2. The result is expressed in radians and has the same data type as x.
ATAN(x,y) returns the arc tangent of x/y. The result is such that if x/y ≥ 0, then 0 ≤ ATAN(x,y) ≤ Π; and, if x/y < 0, then -Π ≤ ATAN(x,y) ≤ 0. The result is expressed in radians and has the same data type as x/y, and has the maximum precision of xand y.