Verified Solution • 2025–26 Session moderate

QJEEM18Maf3f9: JEE Main 2018 Mathematics - Class 12 JEEM18Maf3f9 Solution: Let f(x) = { ( x − 1 ) 1 2 − x , x > 1 , x ≠ 2 k , x = 2…

Let f(x) = {(x−1)12−x,x>1,x≠2k,x=2

Thevaue of k for which f s continuous at x = 2 is :

Multiple Choice Options

  • A 1
  • B e
  • C e-1
  • D e-2

Step-by-Step Verified Solution

Since f(x) is continuous at x = 2.

∴   \therefore\,\,\, lim⁡x→2\mathop {\lim }\limits_{x \to 2} f(x) = f(2)

⇒\Rightarrow    lim⁡x→2\mathop {\lim }\limits_{x \to 2} (x−1)12−x{\left( {x - 1} \right)^{{1 \over {2 - x}}}} = k    ( 1∞{{1^\infty }}   form)

∴\therefore    el{{e^l}} = k

Where ll = lim⁡x→2\mathop {\lim }\limits_{x \to 2} (x −- ll −- 1) ×\times 12−x{1 \over {2 - x}} = lim⁡x→2x−22−x\mathop {\lim }\limits_{x \to 2} {{x - 2} \over {2 - x}}

= lim⁡x→2(x−2x−2)\mathop {\lim }\limits_{x \to 2} \left( {{{x - 2} \over {x - 2}}} \right)

⇒\Rightarrow    k = e −- 1

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