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JEE MainMathematicsToughLogarithm

Equation log⁡4(2x2+x+1)−log⁡2(2x−1)=1\log_{4}(2x^{2} + x + 1) - \log_{2}(2x - 1) = 1 has

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log⁡4(2x2+x+1)−log⁡2(2x−1)=1\log_{4}(2x^{2} + x + 1) - \log_{2}(2x - 1) = 1
Domain (i)
 2x2+x+1>0⇒x∈R\ 2x^{2} + x + 1 > 0 \Rightarrow x \in R
(ii)
2x−1>0⇒x>122x - 1 > 0 \Rightarrow x > \frac{1}{2}.....(1)
2x2+x+12x−1=2⇒x=1,314\frac{\sqrt{2x^{2} + x + 1}}{2x - 1} = 2 \Rightarrow x = 1,\frac{3}{14}.....(2)
(1) & (2), x = 1

Source: Grass-G / M-16 Mathematics Paper 25 Nov First.docx

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