共50条信息
\((1)\)已知\(\cos \beta =-\dfrac{3}{5}\)，且\(\beta \)为第二象限角，求\(\sin \beta \)的值；
\((2)\)已知\(\dfrac{\tan \alpha }{\tan \alpha -6}=-1,\)求值：\(\dfrac{2\cos \alpha -3\sin \alpha }{3\cos \alpha +4\sin \alpha }.\)
设\(α∈\left(0, \dfrac{π}{3}\right) \)，满足\(\sqrt{3}\sin α+\cos α= \dfrac{ \sqrt{6}}{2} \)
\((1)\)求\(\cos \left(α+ \dfrac{π}{6}\right) \)的值；
\((2)\)求\(\cos \left(2α+ \dfrac{7π}{12}\right) \)的值．
进入组卷