Answer:
Step-by-step explanation:
cos x=sin 2x
sin 2x-cos x=0
2 sin x cos x-cos x=0
cos x(2 sin x-1)=0
either cos x=0
[tex]x=\frac{\pi }{2},\frac{3\pi }{2}[/tex]
or
2 sin x-1=0
[tex]sin x=\frac{1}{2} =sin (\frac{\pi }{6}),sin(\pi -\frac{\pi }{6} )\\x=\frac{\pi }{6} ,\frac{5 \pi }{6}[/tex]
