\[1)\ z = 7:\]
\[tg\ \varphi = \frac{b}{a} = \frac{0}{7} = 0;\ \]
\[\varphi = arctg\ 0 = 0.\]
\[Ответ:\ \ 2\pi n.\]
\[2)\ z = - 4:\]
\[tg\ \varphi = \frac{b}{a} = \frac{0}{- 4} = 0;\ \]
\[\varphi = arctg\ 0 = 0.\]
\[Ответ:\ \ \pi + 2\pi n.\]
\[3)\ z = i:\]
\[a = 0;\]
\[\varphi = \frac{\pi}{2}.\]
\[Ответ:\ \ \frac{\pi}{2} + 2\pi n.\ \]
\[4)\ z = - 3i:\]
\[a = 0;\text{\ \ \ }\]
\[\varphi = \frac{\pi}{2}.\]
\[Ответ:\ - \frac{\pi}{2} + 2\pi n.\ \]
\[5)\ z = - 1 + i:\]
\[tg\ \varphi = \frac{b}{a} = \frac{1}{- 1} = - 1;\ \]
\[\varphi = arctg\ ( - 1) = - \frac{\pi}{4}.\]
\[Ответ:\ \ \frac{3\pi}{4} + 2\pi n.\]
\[6)\ z = \sqrt{3} + i:\]
\[tg\ \varphi = \frac{b}{a} = \frac{1}{\sqrt{3}};\ \]
\[\varphi = arctg\frac{1}{\sqrt{3}} = \frac{\pi}{6}.\]
\[Ответ:\ \ \frac{\pi}{6} + 2\pi n.\]
\[7)\ z = 2 - 2i:\]
\[tg\ \varphi = \frac{b}{a} = \frac{- 2}{2} = - 1;\ \]
\[\varphi = arctg\ ( - 1) = - \frac{\pi}{4}.\]
\[Ответ:\ - \frac{\pi}{4} + 2\pi n.\]
\[8)\ z = - 1 - \sqrt{3}i:\]
\[tg\ \varphi = \frac{b}{a} = \frac{- \sqrt{3}}{- 1} = \sqrt{3};\ \]
\[\varphi = arctg\ \sqrt{3} = \frac{\pi}{3}.\]
\[Ответ:\ \ \frac{4\pi}{3} + 2\pi n.\]