# IMARGUMENT

Returns the argument q (theta), an angle expressed in radians, such that:

If this function is not available, run the Setup program to install the Analysis ToolPak. After you install the Analysis ToolPak, you must enable it by using the **Add-Ins** command on the **Tools** menu.

**Syntax**

**IMARGUMENT**(**inumber**)

**Inumber** is a complex number for which you want the argument q.

**Remarks**

- Use COMPLEX to convert real and imaginary coefficients into a complex number.
- If inumber is not in the form x + yi or x + yj, IMARGUMENT returns the #NUM! error value.
- IMARGUMENT is calculated as follows:
where:

and

z = x + yi

**Example**

`IMARGUMENT("3+4i")`

equals 0.927295