Difference between revisions of "ATAN2"

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* [[ATN]] {{text|(arctangent)}}
 
* [[ATN]] {{text|(arctangent)}}
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* [[_PI]] {{text|(QB64 constant value)}}
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Revision as of 17:14, 14 November 2015

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


Syntax

angle! = _ATAN2( y, x)


Parameters

  • y is the vertical axis position(row) as a floating point value.
  • x is the horizontal axis position(column) as a floating point value.

Description

  • The DOUBLE radian angle returned is positive for counter-clockwise angles (upper half-plane, y > 0).
  • The DOUBLE radian angle returned is negative for clockwise angles (lower half-plane, y < 0).
  • _ATAN2(y, x) = ATN(y / x) when x > 0
  • _ATAN2(y, x) = ATN(y / x) + _PI when x < 0 and y >= 0
  • _ATAN2(y, x) = ATN(y / x) - _PI when x < 0 and y < 0
  • _ATAN2(y' x) = _PI / 2 when x = 0 and y > 0
  • _ATAN2(y, x) = -_PI / 2 when x = 0 and y < 0
  • _ATAN2(0, 0) is undefined and the function returns 0.


Errors

See also



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