Returns the arctangent of a number in radians (Double).
The number you want the arctangent of (Double).
The "number" can be any valid numeric exression.
This function takes the ratio of two sides of a right angled triangle (number) and returns the corresponding angle in radians. The ratio is the length of the side opposite the angle divided by the length of the side adjacent to the angle.
The value returned can be in the range -PI/2 to PI/2.
To convert degrees to radians, multiply degrees by PI/180.
To convert radians to degrees, multiply radians by 180/PI.
This function is the inverse of the Tan() function.
The cotangent is the simple inverse of a tangent (1/tangent).
The equivalent .NET function is System.Math.Atn
Atn(1) = 0.785
Dim lPi As Long
lPi = 4 * Atn(1)