共50条信息
已知\({\sin }\left( \alpha +\dfrac{\pi }{6} \right)=\dfrac{2\sqrt{5}}{5}\)，则\({\cos }\left( \dfrac{\pi }{3}-\alpha \right)=\)( )
已知\(\sin(\dfrac{\pi}{4}{+}\alpha){=}\dfrac{2}{3}\)，则\(\cos(\dfrac{\pi}{4}{-}\alpha)\)的值等于\(({ })\)
\(\tan \left( -\dfrac{23}{6}\pi \right)=\)
\( \dfrac{2\cos 80^{\circ}+\cos 160^{\circ}}{\cos 70^{\circ}}\)的值是( )
已知\(\sin (\dfrac{\pi }{3}-\theta )=\dfrac{3}{4}\)，则\(\cos (\dfrac{\pi }{3}+2\theta )=\)
\(\sin 2\)\(α\)\(=\dfrac{24}{25}\)，\(0 < \)\(α\)\( < \dfrac{\pi }{2}\)，则\(\sqrt{2}\cos (\dfrac{\pi }{4}-\alpha )\)的值为 \(.\)
已知\(\sin \left( \dfrac{π}{2}+x\right)= \dfrac{3}{5} \)，则\(\cos 2x\)的值为\((\) \()\)
若\(\dfrac{\sin (\pi -\theta )+\cos (\theta -2\pi )}{\sin \theta +\cos (\pi +\theta )}=\dfrac{1}{2}\) ，则\(\tan \theta = (\) \()\)
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