Site navigation

The set of all values of \(x\) satisfying the inequality \(\log _{\left(x+\frac{1}{x}\right)}\left[\log _{2}\left(\frac{x-1}{x+2}\right)\right]>0\) is

Question and options

The set of all values of xx satisfying the inequality log⁡(x+1x)[log⁡2(x−1x+2)]>0\log _{\left(x+\frac{1}{x}\right)}\left[\log _{2}\left(\frac{x-1}{x+2}\right)\right]>0 is
  1. (2,5)(2,5)
  2. (−5,−2)(-5,-2)
  3. (5,∞)(5,\infty)
  4. Null set

Answer and explanation

Correct answer: D - Null set
The base x+1/x must be positive and not 1, so x > 0, which makes the base >= 2. The inequality then needs log2((x-1)/(x+2)) > 1, i.e. (x-1)/(x+2) > 2, i.e. x < -5, which contradicts x > 0. So no solution.

Practice for these exams

  • IPMAT Indore

Related question papers

Related exam syllabi

More solved explanations in Arithmetic