Question

Вычеслить
Cos 73П/4
Sin(-64/4)
Cos (-45П/6)
Sin 121П/6

Answer 1

$Cos\frac{73\pi }{4}=Cos(18\pi+\frac{\pi }{4})=Cos\frac{\pi }{4}=\frac{\sqrt{2}}{2} \\\\Sin(-\frac{64\pi }{4})=-Sin16\pi=-Sin0^{0}=0\\\\Cos(-\frac{45\pi }{6})=Cos(\frac{15\pi }{2})=Cos(7\pi+\frac{\pi }{2})=Cos\frac{\pi }{2}=0\\\\Sin\frac{121\pi }{6}=Sin(20\pi +\frac{\pi }{6})=Sin\frac{\pi }{6}=\frac{1}{2}$