Trigonometric Identities

$\tan \theta =\frac{\sin \theta }{\cos \theta }$ $\cot \theta =\frac{\cos \theta }{\sin \theta }$

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$(\sin \theta )(\csc \theta )=1$ $(\cos \theta )(\sec \theta )=1$ $(\tan \theta )(\cot \theta )=1$

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${\sin }^2\theta +{\cos }^2\theta =1$ ${\sec }^2\theta -{\tan }^2\theta =1$ ${\csc }^2\theta -{\cot }^2\theta =1$