Q.

Let λR and let the equation E be |x2|-2|x|+|λ-3|=0. Then the largest element in the set S={x+λ:x is an integer solution of E} is _________ .    [2023]

 


Ans.

(5)

|x|2-2|x|+|λ-3|=0 

(|x|-1)2+|λ-3|-1=0                       ...(i) 

Given that x is an integer |x|-1 is an integer

(|x|-1)2-1 is also an integer. Thus |λ-3| is also an integer. Therefore λ is also an integer, (|x|-1)21

Case I: |x|-1=0x=±1 

|λ-3|=1λ=4,2 

Possible values of λ+x=5,3,1. 

Case II: |x|-1=1x=±2 

 |λ-3|=0λ=3

Possible values of x+λ=5,1. 

Considering all possible cases, the maximum value of λ+x=5.