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QUESTION If $\ds\sin\theta=-\frac{1}{2}$ find \ (i) $\cos
\theta$,\ \  (ii) $\sec\theta$.

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ANSWER

$\ds\sin\theta=-\frac{1}{2},$

$\ds{\rm (i)\ }\ \
\cos^2\theta=1-\sin^2\theta=1-\left(-\frac{1}{2}\right)^2=\frac{3}{4},\
\  \cos\theta=\pm\frac{\sqrt{3}}{2}$

$\ds{\rm (ii)\ }\ \
\sec\theta=\frac{1}{\cos\theta}=\pm\frac{2}{\sqrt{3}}$




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