Question bank/JEE Main/Mathematics

JEE MainMathematicsToughInequalities and absolute value

The product of integral solution of the equation
∣∣∣x−1∣−2∣−1∣=2|||x - 1| - 2| - 1| = 2 is −λ- \lambda then find the value of
λ\lambda.

Show answer and solution
∣∣∣x−1∣−2∣−1∣=2|||x - 1| - 2| - 1| = 2
⇒∣∣x−1∣−2∣−1=2\Rightarrow ||x - 1| - 2| - 1 = 2 or ∣∣x−1∣−2∣−1=−2||x - 1| - 2| - 1 = - 2
∣∣x−1∣−2∣=3||x - 1| - 2| = 3........(1) or ∣∣x−1∣−2∣=−1||x - 1| - 2| = - 1 Not possible
Case: 1

∣(x−1∣−2∣=3\mid (x - 1| - 2| = 3
⇒∣x−1∣−2=3\Rightarrow |x - 1| - 2 = 3 or ∣x−1∣−2=−3|x - 1| - 2 = - 3
⇒∣x−1∣=5\Rightarrow |x - 1| = 5 or ∣x−1∣=−1|x - 1| = - 1
⇒x−1=±5\Rightarrow x - 1 = \pm 5
⇒x=5+1,−5+1\Rightarrow x = 5 + 1, - 5 + 1 Not possible
= 6, - 4

Product of integral solutions
=6×(−4)= 6 \times ( - 4)
= - 24

⇒λ=24\Rightarrow \lambda = 24

Source: Grass-G / M-05 Mathematics Paper 10 October.docx

Need a video for this idea?

Scan any doubt from your notes and get a whiteboard explanation.