This function calculates the cotangent of specified complex number.
IMCOT(complex_num)
The complex_num argument is a complex number to return the cotangent for.
An error is returned if the complexn_um argument is not in the form "x+yi" or "x+yj".
Accepts numeric and string data. Returns string data.
IMCOT("2-3i") gives the result -0.0037
IMCOT("1-3i") gives the result 0.0044