Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
JEE Main 202621 JanuaryMorning Shift
Exam
JEE Main
Year
2026
Date
21 January
Shift
Morning Shift
Subject
Mathematics
Chapter
Limits

JEE Main 2026 · 21 January · Morning Shift · Mathematics · Limits

Let f: R arrow(0, ∞) be a twice differentiable function such that...

Let f:R→(0,∞)f: \mathbf{R} \rightarrow(0, \infty) be a twice differentiable function such that f(3)=18,f′(3)=0f(3)=18, f^{\prime}(3)=0 and f′′(3)=4f^{\prime \prime}(3)=4. Then lim⁡x→1\lim _{x \rightarrow 1}\left(\log _{\mathrm{e}}\left(\frac{f(2+x)}{f(3)}\right)^{\frac{18}{(x-1)^{2}}}\right) is equal to :

Options

  1. A1
  2. B18
  3. C2
  4. D9

Correct answer

C. 2

Step-by-step solution

Let T=lim⁡x→1(f(x+2)f(3))18(x−1)2T = \lim_{x \to 1} \left( \dfrac{f(x+2)}{f(3)} \right)^{\dfrac{18}{(x-1)^2}} ; 1∞1^{\infty} form
⇒T=elim⁡x→118(x−1)2(f(x+2)−f(3)f(3))\Rightarrow T = e^{\lim_{x \to 1} \dfrac{18}{(x-1)^2} \left( \dfrac{f(x+2) - f(3)}{f(3)} \right)}
⇒T=elim⁡x→118(x−1)2(f(x+2)−f(3)18)\Rightarrow T = e^{\lim_{x \to 1} \dfrac{18}{(x-1)^2} \left( \dfrac{f(x+2) - f(3)}{18} \right)}
⇒T=elim⁡x→1(f(x+2)−f(3)(x−1)2)\Rightarrow T = e^{\lim_{x \to 1} \left( \dfrac{f(x+2) - f(3)}{(x-1)^2} \right)} 00\dfrac{0}{0} form, apply L'pital
⇒T=elim⁡x→1f′(x+2)2(x−1)\Rightarrow T = e^{\lim_{x \to 1} \dfrac{f'(x+2)}{2(x-1)}} ; 00\dfrac{0}{0} form, apply L'pital
⇒T=elim⁡x→1f′′(x+2)2\Rightarrow T = e^{\lim_{x \to 1} \dfrac{f''(x+2)}{2}} =e42=e2= e^{\dfrac{4}{2}} = e^2
⇒log⁡e(T)=2\Rightarrow \log_e(T) = 2
Practice Limits on Quantrex Academy →

More from Limits

Let _ x → 2 (( (x-2))(rx^2 + (p-2)x - 2p))/((x-2)^2) = 5 for some r, p ∈ ℝ . If the set… JEE Main 2026The value of _ x → 0 ((x^2 ^2 x)/(x^2 - ^2 x)) is: JEE Main 2026Let f(x) = _ y → 0 ((1 - (xy)) (xy))/(y^3) . Then the number of solutions of the equation… JEE Main 2026The product of all possible values of α , for which _ x → 0 ((1 - (α x) ((α+1)x)… JEE Main 2026If _ x → 2 (x^3 - 5x^2 + ax + b) ( x-1 - 1) _e(x-1) = m , then a + b + m is equal to : JEE Main 2026The value of _ x arrow 0 _ e ( (e x) · (e^ 2 x) · … · (e^ 10 x)) e^ 2 -e^ 2 x is equal to JEE Main 2026If _ x arrow 0 e^ (a-1) x +2 ~b x+(c-2) e^ -x x x- _ e (1+x) =2 , then a^ 2 +b^ 2 +c^ 2… JEE Main 2026Let [·] denote the greatest integer function and f(x)= _ n arrow ∞ 1 n^ 3 ∑_ k=1 ^ n [ k^… JEE Main 2026Let α and β be the real numbers such that _ x arrow 0 (1)/(x^3)((α)/(2) ∫_0^x (1)/(1-t^2)… JEE Advanced 2025Let x_0 be the real number such that e^ x_0 +x_0=0 . For a given real number α , define… JEE Advanced 2025Given below are two statements : Statement I : _ x arrow 0 ( ^ -1 x+ _e (1+x)/(1-x) -2 x… JEE Main 2025If the function f(x)=( ( x)- ( x))/( x- x) is continuous at x=0 , then f(0) is equal to… JEE Main 2025_ x arrow 0^ + (5(x)^ (1)/(3) ) _e(1+3 x^2) ( ^ -1 3 x )^2(e^ 5(x)^ (4)/(3) -1) is equal… JEE Main 2025If _ x arrow 1^ + ((x-1)(6+λ (x-1))+μ (1-x))/((x-1)^3)=-1 , where λ, μ ∈ ℝ , then λ+μ is… JEE Main 2025If Lim_ x arrow 0 (( x)/(x))^ (1)/(x^2) =p , then 96 _e p is equal to ______ JEE Main 2025If _ x arrow 0 ( (2 x)+a (4 x)-b)/(x^4) is finite, then (a+b) is equal to : JEE Main 2025 Full Limits list Limits JEE Maths PYQsJEE Mathematics PYQs All JEE Main PYQs