Решебник по геометрии 9 класс Мерзляк Задание 8

\[1)\sin{135{^\circ}} = \sin(90{^\circ} + 45{^\circ}) =\]

\[= \cos{45{^\circ}} = \frac{\sqrt{2}}{2};\]

\[2)\cos{135{^\circ}} = \cos(90{^\circ} + 45{^\circ}) =\]

\[= - \sin{45{^\circ}} = - \frac{\sqrt{2}}{2};\]

\[3)\ tg\ 135{^\circ} = \frac{\sin{135{^\circ}}}{\cos{135{^\circ}}} =\]

\[= \frac{\sqrt{2}}{2}\ :\left( - \frac{\sqrt{2}}{2} \right) = - 1;\]

\[4)\ ctg\ 135{^\circ} = \frac{1}{tg\ 135{^\circ}} = - 1.\]