Question

Решите уравнение sin 2x=√2cosx

Answer 1

$Sin2x=\sqrt{2}Cosx\\\\2Sinx Cosx-\sqrt{2}Cosx=0\\\\Cosx(2Sinx-\sqrt{2})=0\\\\\left[\begin{array}{ccc}Cosx=0\\2Sinx-\sqrt{2}=0 \end{array}\right\\\\1)Cosx=0\\\\x=\frac{\pi }{2}+\pi n,n\in Z\\\\2)2Sinx-\sqrt{2}=0\\\\2Sinx=\sqrt{2}\\\\Sinx=\frac{\sqrt{2} }{2}\\\\x=(-1)^{n}arc Sin\frac{\sqrt{2} }{2}+\pi n,n\in Z\\\\x=(-1)^{n}\frac{\pi }{4}+\pi n,n\in Z\\\\Otvet:\boxed{\frac{\pi }{2}+\pi n;(-1)^{n}\frac{\pi }{4}+\pi n,n\in Z}$