giải phương trình `sin3x=1/2`

sin 3x = $\frac{1}{2}$ $\\$ <=> sin 3x = sin $\frac{\pi}{6}$ $\\$ <=> $\left[\begin{matrix} 3x = \frac{\pi}{6} + k.2\pi\\ 3x = \pi - \frac{\pi}{6} + k.2\pi\end{matrix}\right.$ (K $\in$ $\mathbb{Z}$) $\\$ <=> $\left[\begin{matrix} x = \frac{\pi}{18} + \frac{k.2\pi}{3}\\ x = \frac{5\pi}{18} + \frac{k.2\pi}{3}\end{matrix}\right.$ (K $\in$ $\mathbb{Z}$)