Finding the exact values of $\sin 4x - \sin 2x = 0$ So I've used the double angle formula to turn
$$\sin 4x - \sin 2x = 0$$
$$2\sin2x\cos2x - \sin2x = 0$$
$$\sin2x(2\cos2x - 1) = 0$$

$$\sin2x = 0$$
$$2x = 0$$
$$x = 0$$

$$2\cos2x - 1 = 0$$
$$2\cos2x = 1$$
$$\cos2x = \frac{1}{2}$$
$$2x = 60$$
$$x = 30$$

With this information I am able to use the unit circle to find
$$x = 0,30,180,330,360$$
However, when I looked at the answers, $$x = 0,30,90,150,180,210,270,330,360$$
Can someone tell me how to obtain the rest of the values for $x$.
Thanks

First you should use the natural angle unit, which is the radian. Second, you should write the general solution, which is always a congruence. 
Your equation factors as 
\begin{align*}
2\sin x\cos x(2\cos 2x -1)=0 &\iff\begin{cases}\sin x=0\\ \cos x=0 \\\cos x=\frac12
\end{cases}\\
& \iff 
\begin{cases}
x\equiv 0\mod \pi \\
x\equiv \frac\pi2\mod\pi\\2x\equiv\pm\frac\pi3\mod 2\pi\iff x\pm\frac\pi6\mod \pi
\end{cases}
\end{align*}

