 \text{and}\quad \varphi_1 = \varphi_2+ 2 k \pi,$$
            </div>
            where $k \in \mathbb Z.$
            <p></p>

            <p>In order to make the argument of $z$ a well-defined number, it is sometimes
                restricted to the interval $(-\pi, \pi].$ This special choice is called the <em>principal value</em>
                or the
                <em>main branch</em> of the argument and is written as $\textbf{Arg}(z).$
            </p>

            <p>Note that there is no general 