If $\sec \theta+\tan \theta=2 / 3$, then in which quadrant does $\theta$ lie in?

If $\sec \theta+\tan \theta=2 / 3$, then in which quadrant does $\theta$ lie in?
  1. I
  2. II
  3. III
  4. IV

Solution

$ \begin{aligned} & \text { } \sec \theta+\tan \theta=\frac{2}{3} \\ & \Rightarrow \sec \theta-\tan \theta=\frac{3}{2} \end{aligned} $ Eqs. (i) + (ii) $ \Rightarrow \quad 2 \sec \theta=\frac{13}{6} \Rightarrow \sec \theta=\frac{13}{12} $ Eqs. (i) -(ii) $ \Rightarrow \quad 2 \tan \theta=-\frac{5}{6} \Rightarrow \tan \theta=-\frac{5}{12} $ $\therefore \sec \theta$ is positive and $\tan \theta$ is negative $\therefore \theta$ lies in IV quadrant Hence, option (4) is correct

Asked in: AP EAMCET 2020 (22 Sep Shift 2)

Practice more Trigonometric Ratios & Identities questions on Aicharya