\[1)\ z = x > 0:\]
\[\varphi = 0 = 2\pi n.\]
\[2)\ z = yi;\text{\ \ \ y} > 0:\]
\[\varphi = \frac{5\pi}{2} = \frac{\pi}{2} + 2\pi n;\]
\[3)\ 2\pi < \varphi < 3\pi;\]
\[z = x + iy;\text{\ \ \ y} > 0:\]
\[2\pi n < \varphi < \pi + 2\pi n.\]
\[4)\ 0 \leq \varphi < 2\pi;\]
\[вся\ плоскость;\text{\ \ z} \neq 0:\]
\[2\pi n \leq \varphi < 2\pi + 2\pi n.\]