Sum, Difference, and Multiple-Angle Formulas · Easy problem

$\dfrac{\sqrt3}{2}\sin x+\dfrac12\cos x$

$\dfrac{\sqrt3}{3}\sin x+\dfrac12\cos x$

$\dfrac{2}{\sqrt3}\sin x+\dfrac12\cos x$

$\dfrac{\sqrt3}{2}\sin x-\dfrac12\cos x$