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AP EAMCET · Maths · Functions

xR/x2-2x-8log2-x-x2 is a real number

  1. A (-,-4]U[4,)
  2. B ϕ
  3. C -1,2
  4. D (-,-4]-1,2[4,)
Verified Solution

Answer & Solution

Correct Answer

(B) ϕ

Step-by-step Solution

Detailed explanation

Let fx=x2-2x-8log2-x-x2 ⇒fx=x2-2x-8log-x2-x+1 log-x2-x+1 is defined for -x2-x+1>0 ⇒x2+x-1<0 ⇒x--1+52x--1-52<0 ⇒x∈-1-52,-1+52 ⇒x∈-1.61,0.61   ....i And, x2-2x-8≥0 Put x=t ⇒t2-2t-8≥0…