\[\lbrack 0;\ 3\pi\rbrack.\]
\[1)\ tg\ x \geq 3\]
\[arctg\ 3 + \pi n \leq x < \frac{\pi}{2} + \pi n.\]
\[Ответ:\ \ \]
\[arctg\ 3 \leq x < \frac{\pi}{2};\text{\ \ \ }\]
\[arctg\ 3 + \pi \leq x < \frac{3\pi}{2};\ \]
\[arctg\ 3 + 2\pi \leq x < \frac{5\pi}{2}.\]
\[2)\ tg\ x < 4\]
\[- \frac{\pi}{2} + \pi n < x < arctg\ 4 + \pi n.\]
\[Ответ:\ \ \]
\[0 \leq x < arctg\ 4;\text{\ \ \ }\]
\[\frac{\pi}{2} < x < arctg\ 4 + \pi;\text{\ \ }\]
\[\ \frac{3\pi}{2} < x < arctg\ 4 + 2\pi;\text{\ \ \ }\]
\[\frac{5\pi}{2} < x \leq 3\pi.\]
\[3)\ tg\ x \leq - 4\]
\[- \frac{\pi}{2} + \pi n < x \leq - arctg\ 4 + \pi n.\]
\[Ответ:\ \ \]
\[\frac{\pi}{2} < x \leq - arctg\ 4 + \pi;\text{\ \ \ }\]
\[\frac{3\pi}{2} < x \leq - arctg\ 4 + 2\pi;\]
\[\ \frac{5\pi}{2} < x \leq - arctg\ 4 + 3\pi.\]
\[4)\ tg\ x > - 3\]
\[- arctg\ 3 + \pi n < x < \frac{\pi}{2} + \pi n.\]
\[Ответ:\ \ 0 \leq x < \frac{\pi}{2};\text{\ \ \ }\]
\[- arctg\ 3 + \pi < x < \frac{3\pi}{2};\text{\ \ \ }\]
\[- arctg\ 3 + 2\pi < x < \frac{5\pi}{2};\text{\ \ }\]
\[- arctg\ 3 + 3\pi < x \leq 3\pi.\]