If $\tan \theta=2$ and $\theta$ lies in the third quadrant, then the value of $\sec \theta$ is

If $\tan \theta=2$ and $\theta$ lies in the third quadrant, then the value of $\sec \theta$ is
  1. $-\sqrt{5}$
  2. $\sqrt{3}$
  3. $-\sqrt{2}$
  4. $\sqrt{5}$

Solution

$\sec ^{2} \theta=1+(2)^{2}=5$ $\therefore \sec \theta=-\sqrt{5}$ $\quad\quad\left[\because \theta\right.$ lies in $3^{\text {nd }}$ quadrant. $]$

Asked in: MHT CET 2020 (13 Oct Shift 2)

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