find the general solution of:
sin(2x+30)=cos3x
List of trigonometric identities - Wikipedia, the free encyclopedia
$\displaystyle \cos 3\theta = 4 \cos^3\theta - 3 \cos \theta$
$\displaystyle \sin (2x+30) = \sin (2x) \cos (30) + \cos (2x) \sin (30)$
$\displaystyle \cos (3x) = 4 \cos^3 (x) - 3 \cos (x)$
$\displaystyle \sin (2x) \cos (30) + \cos (2x) \sin (30) = 4 \cos^3 (x) - 3 \cos (x)$
If you need more help please show what working you've done. I'm not prepared to do this question for you