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QUESTION Find the solutions of $\tan\theta=-1$ for
$0<\theta\leq2\pi$.



ANSWER

$\tan\theta=-1:$ The tangent is negative in the second and fourth
quadrants therefore the solutions are
$\ds\theta=\pi-\frac{\pi}{4}$ and $\theta=\ds 2\pi-\frac{\pi}{4}$
i.e. $\ds\theta=\frac{3\pi}{4}$ and $\ds\frac{7\pi}{4}.$




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