This function returns the argument theta, which is an angle expressed in radians.
IMARGUMENT(complexnum)
The complexnum argument is a complex number for which to return the argument theta.
An error is returned if the complexnum argument is not in the form "x+yi" or "x+yj". For more information, refer to Complex Numbers.
Accepts number and string data. Returns number data.
IMARGUMENT("3+5j")