Câu hỏi: Tìm nghiệm của phương trình \(\sin 5{\rm{x}} + {\rm{co}}{{\rm{s}}^2}{\rm{x}} - {\sin ^2}{\rm{x}} = 0\)

A.  \(\left[ {\begin{array}{*{20}{l}}{{\rm{x}} =  - \frac{{\rm{\pi }}}{6} + {\rm{k}}\frac{{\rm{\pi }}}{3}}\\{{\rm{x}} =  - \frac{{\rm{\pi }}}{{14}} + {\rm{k}}\frac{{\rm{\pi }}}{7}}\end{array}} \right.\)

B. \(\left[ {\begin{array}{*{20}{l}}{{\rm{x}} =  - \frac{{\rm{\pi }}}{6} + {\rm{k}}\frac{{{\rm{2\pi }}}}{3}}\\{{\rm{x}} =  - \frac{{\rm{\pi }}}{{14}} + {\rm{k}}\frac{{{\rm{2\pi }}}}{7}}\end{array}} \right.\)

C. \(\left[ {\begin{array}{*{20}{l}} {{\rm{x}} = \frac{{\rm{\pi }}}{6} + {\rm{k2\pi }}}\\{{\rm{x}} = \frac{{\rm{\pi }}}{{14}} + {\rm{k2\pi }}}\end{array}} \right.\)

D. \(\left[ {\begin{array}{*{20}{l}}{{\rm{x}} =  - \frac{{\rm{\pi }}}{6} + {\rm{k2\pi }}}\\{{\rm{x}} =  - \frac{{\rm{\pi }}}{{14}} + {\rm{k2\pi }}}\end{array}} \right.\)