Question

Вычислите. cos(-480°) - √2sin(-7п/4)​

Answer 1

Ответ:cos(-480°) = cos(360° - 480°) = cos(-120°) = cos(240°) = cos(180° + 60°) = -cos(60°) = -1/2

sin(-7π/4) = sin(-π/4) = -sin(π/4) = -1/√2

Подставляем значения: cos(-480°) - √2sin(-7п/4) = -1/2 - √2(-1/√2) = -1/2 + 1 = 1/2

Объяснение: просто изи с тебя

Answer 2

$\displaystyle\bf\\Cos(-480^\circ)-\sqrt{2} Sin\Big(-\frac{7\pi }{4} \Big)=Cos480^\circ+\sqrt{2} \ Sin\frac{7\pi }{4} =\\\\\\=Cos\Big(360^\circ+120^\circ\Big)+\sqrt{2} \ Sin\Big(2\pi -\frac{\pi }{4} \Big)=\\\\\\=Cos120^\circ-\sqrt{2} \ Sin\frac{\pi }{4} =-\frac{1}{2} -\sqrt{2} \cdot \frac{1}{\sqrt{2} }=-0,5-1=-1,5$