Medium MCQ +4 / -1 PYQ · JEE Mains 2021

The domain of the function

$$f(x) = {\sin ^{ - 1}}\left( {{{3{x^2} + x - 1} \over {{{(x - 1)}^2}}}} \right) + {\cos ^{ - 1}}\left( {{{x - 1} \over {x + 1}}} \right)$$ is :

  1. A $\left[ {0,{1 \over 4}} \right]$
  2. B $[ - 2,0] \cup \left[ {{1 \over 4},{1 \over 2}} \right]$
  3. C $\left[ {{1 \over 4},{1 \over 2}} \right] \cup \{ 0\}$ Correct answer
  4. D $\left[ {0,{1 \over 2}} \right]$

Solution

$$f(x) = {\sin ^{ - 1}}\left( {{{3{x^2} + x - 1} \over {{{(x - 1)}^2}}}} \right) + {\cos ^{ - 1}}\left( {{{x - 1} \over {x + 1}}} \right)$$<br><br>$- 1 \le {{x - 1} \over {x + 1}} \le 1 \Rightarrow 0 \le x &lt; \infty$ .... (1)<br><br>$$ - 1 \le {{3{x^2} + x - 1} \over {{{(x - 1)}^2}}} \le 1 \Rightarrow x \in \left[ {{{ - 1} \over 4},{1 \over 2}} \right] \cup \{ 0\} $$ .... (2)<br><br>(1) &amp; (2)<br><br>$\Rightarrow$ Domain = $\left[ {{1 \over 4},{1 \over 2}} \right] \cup \{ 0\}$

About this question

Subject: Mathematics · Chapter: Inverse Trigonometric Functions · Topic: Domain and Range

This question is part of PrepWiser's free JEE Main question bank. 65 more solved questions on Inverse Trigonometric Functions are available — start with the harder ones if your accuracy is >70%.

Drill 25 more like these. Every day. Free.

PrepWiser turns these solved questions into a daily practice loop. Chapter-wise drills, full mocks, AI doubt chat. No auto-renew.

Start free →