Chapter 5: Problem 8
Suppose \(-\frac{\pi}{2}<\theta<0\) and \(\cos \theta=\frac{1}{5} .\) Evaluate: (a) \(\sin \theta\) (b) \(\tan \theta\)
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Chapter 5: Problem 8
Suppose \(-\frac{\pi}{2}<\theta<0\) and \(\cos \theta=\frac{1}{5} .\) Evaluate: (a) \(\sin \theta\) (b) \(\tan \theta\)
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Find exact expressions for the indicated quantities, given that $$ \cos \frac{\pi}{12}=\frac{\sqrt{2+\sqrt{3}}}{2} \text { and } \sin \frac{\pi}{8}=\frac{\sqrt{2-\sqrt{2}}}{2} $$ [These values for \(\cos \frac{\pi}{12}\) and \(\sin \frac{\pi}{8}\) will be derived in Examples 4 and 5 in Section 6.3.] $$ \sin \frac{5 \pi}{12} $$
Suppose \(u\) and \(v\) are in the interval \(\left(\frac{\pi}{2}, \pi\right),\) with \(\tan u=-2\) and \(\tan v=-3\) Find exact expressions for the indicated quantities. $$ \cos (v-6 \pi) $$
Show that $$ \sin ^{2} \theta=\frac{\tan ^{2} \theta}{1+\tan ^{2} \theta} $$ for all \(\theta\) except odd multiples of \(\frac{\pi}{2}\)
Show that $$ (\cos \theta+\sin \theta)^{2}=1+2 \cos \theta \sin \theta $$ for every number \(\theta\). [Expressions such as \(\cos \theta \sin \theta\) mean $$ (\cos \theta)(\sin \theta), \operatorname{not} \cos (\theta \sin \theta) .] $$
Suppose \(u\) and \(v\) are in the interval \(\left(\frac{\pi}{2}, \pi\right),\) with \(\tan u=-2\) and \(\tan v=-3\) Find exact expressions for the indicated quantities. $$ \tan \left(\frac{\pi}{2}-u\right) $$
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