ATAN()

Table 1. `ATAN` Function Parameter
Parameter	Description
number	An expression of a numeric type

Table 1. ATAN Function Parameter

Parameter

Description

number

An expression of a numeric type

`ATAN2()`

Two-argument arc tangent

Result type

DOUBLE PRECISION

Syntax

ATAN2 (y, x)

Table 1. `ATAN2` Function Parameters
Parameter	Description
y	An expression of a numeric type
x	An expression of a numeric type

Returns the angle whose sine-to-cosine ratio is given by the two arguments, and whose sine and cosine signs correspond to the signs of the arguments.This allows results across the entire circle, including the angles -pi/2 and pi/2.

The result is an angle in the range [-pi, pi].
If x is negative, the result is pi if y is 0, and -pi if y is -0.
If both y and x are 0, the result is meaningless.An error will be raised if both arguments are 0.

A fully equivalent description of this function is the following: ATAN2(y, x) is the angle between the positive X-axis and the line from the origin to the point (x, y).This also makes it obvious that ATAN2(0, 0) is undefined.
If x is greater than 0, ATAN2(y, x) is the same as ATAN(y/x).
If both sine and cosine of the angle are already known, ATAN2(sin, cos) gives the angle.