<s>[INST] If $\sin(x+28^\circ)=\cos(3x-78^\circ)$, then find x $$\sin(x+28^\circ)=\sin (90^\circ-3x+78^\circ)$$
$$x+28^\circ=168^\circ-3x$$
$$x=35^\circ$$
Pretty straightforward question, but then answer is $35^\circ$ and $8^\circ$. How is $8^\circ$ the answer?
 [/INST] Hint: Use $$\sin(x)-\cos(y)=-2 \sin \left(-\frac{x}{2}-\frac{y}{2}+\frac{\pi
   }{4}\right) \sin
   \left(-\frac{x}{2}+\frac{y}{2}+\frac{\pi }{4}\right)$$
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