The _ATAN2 function returns the radian angle between the positive x-axis of a plane and the point given by the coordinates (x, y).

## Syntax

angle! = _ATAN2(y, x)

## Parameter(s)

- y is the vertical axis position (row) as a positive, zero or negative floating point value.
- x is the horizontal axis position (column) as a positive, zero or negative floating point value.

## Description

- The DOUBLE radian angle returned is
**positive**for upper row values where y > 0. - The DOUBLE radian angle returned is 0 when x > 0 and _PI when x < 0 where y = 0
- The DOUBLE radian angle returned is
**negative**for lower row values where y < 0. - _ATAN2(0, 0) is undefined and the function returns 0 instead of a division error.

## Error(s)

- With ATN(y / x), x can never be 0 as that would create a Division by Zero ERROR Codes 11 or #IND.

## See Also

- ATN (arctangent)
- _PI (QB64 function)
- Mathematical Operations
- Atan2 reference