\(\Leftrightarrow\sqrt{3}sinx+3cosx=3\)
\(\Leftrightarrow\frac{1}{2}sinx+\frac{\sqrt{3}}{2}cosx=\frac{\sqrt{3}}{2}\)
\(\Leftrightarrow sin\left(x+\frac{\pi}{3}\right)=\frac{\sqrt{3}}{2}\)
\(\Leftrightarrow\left[{}\begin{matrix}x+\frac{\pi}{3}=\frac{\pi}{3}+k2\pi\\x+\frac{\pi}{3}=\frac{2\pi}{3}+k2\pi\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=k2\pi\\x=\frac{\pi}{3}+k2\pi\end{matrix}\right.\)