The number argument can be any valid numeric expression that expresses an angle in radians.
The Cos function takes an angle and returns the ratio of two sides of a right triangle. The ratio is the length of the side adjacent to the angle divided by the length of the hypotenuse. The result lies in the range -1 to 1.
To convert degrees to radians, multiply degrees by pi/180. To convert radians to degrees, multiply radians by 180/pi.
The following example uses the Cos function to return the cosine of an angle:
Dim MyAngle, MySecant
MyAngle = 1.3 ' Define angle in radians.
MySecant = 1 / Cos(MyAngle) ' Calculate secant.