Tan takes an angle and returns the ratio of two sides of a right triangle. The ratio is the length of the side opposite the angle divided by the length of the side adjacent to the angle.
The following example uses the Tan function to return the tangent of an angle:
Dim MyAngle, MyCotangent MyAngle = 1.3 ' Define angle in radians. MyCotangent = 1 / Tan(MyAngle) ' Calculate cotangent.