Giải các phương trình sau:
a) \(\sqrt 3 \cot \left( {2x - 1} \right) + 1 = 0\). b) \(2\sin x + 2\cos x = \sqrt 2 \).
A.a)\(S = \left\{ {\frac{1}{2} - \frac{\pi }{6} + k\frac{\pi }{2},\,\,k \in Z} \right\}\).
b)\(S = \left\{ { - \frac{\pi }{{12}} + k2\pi ,\,\,k \in Z} \right\} \cup \left\{ {\frac{{7\pi }}{{12}} + k2\pi ,\,\,k \in Z} \right\}\).
B.a)\(S = \left\{ {\frac{1}{3} - \frac{\pi }{6} + k\frac{\pi }{2},\,\,k \in Z} \right\}\).
b)\(S = \left\{ { - \frac{\pi }{{12}} + k2\pi ,\,\,k \in Z} \right\} \cup \left\{ {\frac{{7\pi }}{{12}} + k2\pi ,\,\,k \in Z} \right\}\).
C.a)\(S = \left\{ {\frac{1}{2} - \frac{\pi }{4} + k\frac{\pi }{2},\,\,k \in Z} \right\}\).
b)\(S = \left\{ { - \frac{\pi }{{12}} + k2\pi ,\,\,k \in Z} \right\} \cup \left\{ {\frac{{7\pi }}{{12}} + k2\pi ,\,\,k \in Z} \right\}\).
D.a)\(S = \left\{ {\frac{1}{2} - \frac{\pi }{6} + k\frac{\pi }{2},\,\,k \in Z} \right\}\).
b)\(S = \left\{ { - \frac{\pi }{{12}} + k2\pi ,\,\,k \in Z} \right\} \cup \left\{ {\frac{{7\pi }}{{13}} + k2\pi ,\,\,k \in Z} \right\}\).
