1. Вычислите: 5) $$\frac{10 \sin 200^{\circ}}{\sin 100^{\circ} \cos 100^{\circ}}$$

$$\frac{10 \sin (180^{\circ}+20^{\circ})}{\frac{1}{2} \sin (2 \cdot 100^{\circ})} = \frac{10 (-\sin 20^{\circ})}{\frac{1}{2} \sin 200^{\circ}} = \frac{-20 \sin 20^{\circ}}{\sin (180^{\circ}+20^{\circ})} = \frac{-20 \sin 20^{\circ}}{-\sin 20^{\circ}} = 20$$