trigonometry

Related Questions

• If $x=y\cos \frac{2\pi }{3}=z\cos \frac{4\pi }{3}$, then $xy+yz+zx=$

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• If $\tan \theta =\frac{x\,\sin \,\varphi }{1-x\,\cos \,\varphi }$ and $\tan \,\varphi =\frac{y\sin \,\theta }{1-y\,\cos \,\theta }$, then $\frac{x}{y}=$

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• $\tan 3A-\tan 2A-\tan A=$

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• If $\sin \theta =\sqrt{3}\cos \theta ,-\pi <\theta <0$, then $\theta =$

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• $\sin 50{}^\circ -\sin 70{}^\circ +\sin 10{}^\circ =$

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