This function calculates the tangent of specified complex number.
IMTAN(complex_num)
The complex_num argument is a complex number to return the tangent for.
An error is returned if the complex_num argument is not in the form "x+yi" or "x+yj".
Accepts numeric and string data. Returns string data.
IMTAN("8+2i") gives the result -0.0109
IMTAN("9+3i") gives the result -0.0037