COTAN is the trigonometric cotangent function. The COTAN function accepts a number that indicates the number of radians in an angle, and returns the cotangent of that angle.

The method used for calculating the COTAN(x) is identical to the method for calculating TAN(x). However, because COTAN(x) is the reciprocal of TAN(x), the final calculation for COTAN(x) is obtained by use of the relationships shown in TAN/COTAN Calculation.