For the purposes of PROMOTIC system, it is more usefull to use the method: Pm.Atan.
n = Atn(nValue)
|nValue||(Double) Any valid numeric expression.|
To convert degrees to radians, multiply degrees by pi/180. To convert radians to degrees, multiply radians by 180/pi.
Atn is the inverse trigonometric function of Tan, which takes an angle as its argument and returns the ratio of two sides of a right triangle. Do not confuse Atn with the cotangent, which is the simple inverse of a tangent (cotangent=1/tangent).
pi = 4 * Atn(1) 'calculate the value of Pi
Arcsin = Atn(x / Sqr(-x*x + 1))
Arccos = Atn(-x / Sqr(-x*x + 1)) + 2 * Atn(1)
Arccotan = Atn(x) + 2 * Atn(1)