Решебник по алгебре и начала математического анализа 11 класс Колягин Задание 34

\[1)\cos\frac{\pi}{7}\ и\ \cos\frac{8\pi}{9};\]

\[0 < \frac{\pi}{7} < \frac{8\pi}{9} < \pi;\]

\[\cos\frac{\pi}{7} > \cos\frac{8\pi}{9}.\]

\[2)\cos\frac{8\pi}{7}\ и\ \cos\frac{10\pi}{7};\]

\[\pi < \frac{8\pi}{7} < \frac{10\pi}{7} < 2\pi;\]

\[\cos\frac{8\pi}{7} < \cos\frac{10\pi}{7}.\]

\[3)\cos\left( - \frac{6\pi}{7} \right)\ и\ \cos\left( - \frac{\pi}{8} \right);\]

\[- \pi < - \frac{6\pi}{7} < - \frac{\pi}{8} < 0;\]

\[\cos\left( - \frac{6\pi}{7} \right) < \cos\left( - \frac{\pi}{8} \right).\]

\[4)\cos\left( - \frac{8\pi}{7} \right)\ и\ \cos\left( - \frac{9\pi}{7} \right);\]

\[- 2\pi < - \frac{9\pi}{7} < - \frac{8\pi}{7} < - \pi;\]

\[\cos\left( - \frac{8\pi}{7} \right) < \cos\left( - \frac{9\pi}{7} \right).\]

\[5)\cos 1\ и\ \cos 3;\]

\[0 < 1 < 3 < \pi;\]

\[\cos 1 > \cos 3.\]

\[6)\cos 4\ и\ \cos 5;\]

\[\pi < 4 < 5 < 2\pi;\]

\[\cos 4 < \cos 5.\]