Question

If $\cos \theta =\frac{9}{15}$ then find $\sec \theta$

Answer 1

$\cos \theta =\frac{9}{15}$ is positive.

$\therefore \theta$ lies in the first or fourth quadrant.

We know that, $\sec \theta =\frac{1}{\cos \theta }$

$\Rightarrow \sec \theta =\frac{1}{\cos \theta }=\frac{1}{\frac{9}{15}}=\frac{15}{9}$

$\therefore \sec \theta =\frac{15}{9}=\frac{5}{3}$

$\therefore \sec \theta =\frac{5}{3}$