Phương trình \(\sqrt 3 {\co...

Câu hỏi: Phương trình \(\sqrt 3 {\cot ^2}x - 4\cot x + \sqrt 3 = 0\) có nghiệm là:

A. \(\left[ \begin{array}{l}x = \dfrac{\pi }{3} + k\pi \\x = \dfrac{\pi }{6} + k\pi \end{array} \right.\,\,\left( {k \in Z} \right)\)

B. \(\left[ \begin{array}{l}x = \dfrac{\pi }{3} + k2\pi \\x = \dfrac{\pi }{6} + k2\pi \end{array} \right.\,\,\left( {k \in Z} \right)\)

C. \(\left[ \begin{array}{l}x = - \dfrac{\pi }{3} + k\pi \\x = - \dfrac{\pi }{6} + k\pi \end{array} \right.\,\,\left( {k \in Z} \right)\)

D. \(\left[ \begin{array}{l}x = - \dfrac{\pi }{3} + k2\pi \\x = \dfrac{\pi }{6} + k\pi \end{array} \right.\,\,\left( {k \in Z} \right)\)