Find the value of $\theta$, which satisfy $3 − 2 \cos\theta − 4 \sin\theta − \cos 2\theta + \sin2\theta = 0$. We have to find the value of $\theta$, which satisfy $3 − 2 \cos\theta − 4 \sin\theta − \cos 2\theta + \sin2\theta = 0$.
I could not get any start how to solve it . 

HINT:
$$4-2\cos x+2\sin x\cos x-4\sin x=1+\cos2x$$
$$-(\cos x-2)+\sin x(\cos x-2)=\cos^2x$$
$$-(\cos x-2)(1-\sin x)=1-\sin^2x$$
