3) 16 cos135° sin120° =

3) Вычислим значение выражения 16 cos135° sin120° .

cos135° = cos(180° - 45°) = -cos45° = $$\frac{-\sqrt{2}}{2}$$

sin120° = sin(180° - 60°) = sin60° = $$\frac{\sqrt{3}}{2}$$

16 cos135° sin120° = 16 * $$\frac{-\sqrt{2}}{2}$$ * $$\frac{\sqrt{3}}{2}$$ = $$\frac{-16\sqrt{6}}{4}$$ = -4$$\sqrt{6}$$

Ответ: -4$$\sqrt{6}$$