Tìm nghiệm phương trình sau: \( \left( {1 - \tan \frac{x}{2}} \right) \left( {1 + { \mathop{ \rm s} \nolimits} { \rm{inx}}} \right) = 1 + \tan \frac{x}{2} \)
A.\(\left[ \begin{array}{l}x = k2\pi \left( {k \in Z} \right)\\x = \frac{\pi }{4} + m2\pi \left( {m \in Z} \right)\end{array} \right.\)
B.\(\left[ \begin{array}{l}x = k2\pi \;\left( {k \in Z} \right)\\x = \frac{{3\pi }}{2} + m2\pi \;\left( {m \in Z} \right)\end{array} \right.\)
C.\(\left[ \begin{array}{l}x = k\pi \;\left( {k \in Z} \right)\\x = \frac{\pi }{2} + m\pi \;\left( {m \in Z} \right)\end{array} \right.\)
D.\(\left[ \begin{array}{l}x = k2\pi \left( {k \in Z} \right)\\x = \frac{\pi }{2} + m2\pi \;\left( {m \in Z} \right)\end{array} \right.\)