Question

помогите решить пожалуйста очень срочно!!! отдам все баллы!!!

Answer 1

$1)f(x)=Cosx\\\\f(\frac{2\pi }{3})=Cos\frac{2\pi }{3}=Cos(\pi-\frac{\pi }{3})=-Cos\frac{\pi }{3}=\boxed{-\frac{1}{2}}\\\\f(270^{0} )=Cos270^{0} =\boxed0\\\\f(\frac{45\pi }{4})=Cos\frac{45\pi }{4}=Cos(10\pi+\frac{5\pi }{4} )=Cos\frac{5\pi }{4}=Cos(\pi+\frac{\pi }{4})=\\\\=-Cos\frac{\pi }{4}=\boxed{-\frac{\sqrt{2} }{2}}\\\\f(-1800^{0} )=Cos(-1800^{0})=Cos(5*360^{0} +0^{0} )=Cos0^{0}=\boxed1$

$2)f(x)=Sinx\\\\f(\frac{2\pi }{3})=Sin\frac{2\pi }{3}=Sin(\pi-\frac{\pi }{3})=Sin\frac{\pi }{3}=\boxed{\frac{\sqrt{3} }{2}}\\\\f(270^{0} )=Sin270^{0} =\boxed{-1}\\\\f(\frac{45\pi }{4})=Sin\frac{45\pi }{4}=Sin(10\pi+\frac{5\pi }{4} )=Sin\frac{5\pi }{4}=Sin(\pi+\frac{\pi }{4})=\\\\=-Sin\frac{\pi }{4}=\boxed{-\frac{\sqrt{2} }{2}}\\\\f(-1800^{0} )=Sin(-1800^{0})=-Sin(5*360^{0} +0^{0} )=-Sin0^{0}=\boxed0$