 However, if we take the values of $\arg (z_1)$ and $\arg (z_2)$
                    just used and select the value
                    \[
                    \Arg\left(z_1z_2\right) + 2\pi = -\frac{\pi}{2}+ 2\pi = \frac{3\pi}{2}
                    \]
                    of $\arg (z_1z_2),$ we find that equation (\ref{arg-product}) is satisfied.
                </p>
            </div>

            <div class="practice">
                <p>
                    <strong>Exercise:</strong>
                    