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.
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.