共50条信息
已知\(0 < α < \)\(\dfrac{\pi }{{2}}\) \( < β < π\),\(\tan \dfrac{α}{2}= \dfrac{1}{2},\cos (β-α)= \dfrac{ \sqrt{2}}{10} \)
\((1)\)求\(\dfrac{\cos 2\alpha }{\sqrt{2}\cos (\dfrac{\pi }{4}+\alpha )\sin \alpha }\) 的值
\((2)\)求\(β\)的值
进入组卷