Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
JEE Main 20264 AprilEvening Shift
Exam
JEE Main
Year
2026
Date
4 April
Shift
Evening Shift
Subject
Mathematics
Chapter
Continuity and Differentiability

JEE Main 2026 · 4 April · Evening Shift · Mathematics · Continuity and Differentiability

Let f(x)= cases e^ x-1 , & x<0 x^2-5x+6, & x ≥ 0 cases and...

Let f(x)=f(x)=\begin{cases} e^{x-1}, & x<0 \\ x^2-5x+6, & x \geq 0 \end{cases}$andandg(x)=f(|x|)+|f(x)|.Ifthenumberofpointswhere. If the number of points wheregisnotcontinuousandisnotdifferentiableareis not continuous and is not differentiable are\alphaandand\betarespectively,thenrespectively, then\alpha+\beta$ is equal to ______

Correct answer

0

Step-by-step solution

We are given the function:

f(x)=f(x) =\begin{cases} e^{x-1}, & x < 0 \\ x^2 - 5x + 6, & x \geq 0 \end{cases}<br><br>We need to analyze the continuity and differentiability of $g(x) = f(|x|) + |f(x)|$.<br><br>For $x < 0$, $|x| = -x > 0$. Thus, $f(|x|) = (-x)^2 - 5(-x) + 6 = x^2 + 5x + 6$.<br>Also, for $x < 0$, $f(x) = e^{x-1} > 0$, so $|f(x)| = e^{x-1}$.<br>Therefore, for $x < 0$, $g(x) = x^2 + 5x + 6 + e^{x-1}$.<br><br>For $x \geq 0$, $|x| = x$. Thus, $f(|x|) = f(x) = x^2 - 5x + 6$.<br>Therefore, for $x \geq 0$, $g(x) = x^2 - 5x + 6 + |x^2 - 5x + 6|$.<br><br>Let us check the continuity of $g(x)$ at $x = 0$:<br>$\lim_{x \to 0^-} g(x) = \lim_{x \to 0^-} (x^2 + 5x + 6 + e^{x-1}) = 6 + \dfrac{1}{e}$<br>$\lim_{x \to 0^+} g(x) = \lim_{x \to 0^+} (x^2 - 5x + 6 + |x^2 - 5x + 6|) = 6 + 6 = 12$<br>$g(0) = 12$<br><br>Since $\lim_{x \to 0^-} g(x) \neq \lim_{x \to 0^+} g(x)$, $g(x)$ is discontinuous at $x = 0$. For all other $x$, $g(x)$ is a sum of continuous functions and is therefore continuous. <br>Thus, the number of points of discontinuity is $\alpha = 1$.<br><br>Now, let us check the differentiability of $g(x)$.<br>Since $g(x)$ is discontinuous at $x = 0$, it is not differentiable at $x = 0$.<br><br>For $x < 0$, $g(x) = x^2 + 5x + 6 + e^{x-1}$, which is differentiable everywhere in its domain.<br><br>For $x > 0$, we can rewrite $g(x)$ by analyzing the sign of $x^2 - 5x + 6 = (x-2)(x-3)$:<br>$g(x) = $\begin{cases} 2(x^2 - 5x + 6), & x \in (0, 2] \cup [3, \infty) \\ 0, & x \in (2, 3) \end{cases}

Differentiating g(x)g(x) for x>0,x≠2,3x > 0, x \neq 2, 3:
g′(x)=g'(x) =\begin{cases} 4x - 10, & x \in (0, 2) \cup (3, \infty) \\ 0, & x \in (2, 3) \end{cases}$<br><br>Checkingdifferentiabilityat<br><br>Checking differentiability atx = 2:<br>:<br>g'(2^-) = 4(2) - 10 = -2<br><br>g'(2^+) = 0<br>Since<br>Sinceg'(2^-) \neq g'(2^+),,g(x)isnotdifferentiableatis not differentiable atx = 2.<br><br>Checkingdifferentiabilityat.<br><br>Checking differentiability atx = 3:<br>:<br>g'(3^-) = 0<br><br>g'(3^+) = 4(3) - 10 = 2<br>Since<br>Sinceg'(3^-) \neq g'(3^+),,g(x)isnotdifferentiableatis not differentiable atx = 3.<br><br>Thus,.<br><br>Thus,g(x)isnotdifferentiableatexactlythreepoints:is not differentiable at exactly three points:x = 0, 2, 3.<br>So,thenumberofpointsofnon−differentiabilityis.<br>So, the number of points of non-differentiability is\beta = 3.<br><br>Finally,.<br><br>Finally,\alpha + \beta = 1 + 3 = 4.<br><br>Answer:.<br><br>Answer:4$
Practice Continuity and Differentiability on Quantrex Academy →

More from Continuity and Differentiability

Let ℝ denote the set of all real numbers. Let f : ℝ arrow ℝ be an arbitrary function and… JEE Advanced 2026Consider the function f : (-(π)/(2), (π)/(2)) arrow (-∞, ∞) defined by f(x) = (|x| + |x… JEE Advanced 2026For a real number α , let [α] denote the greatest integer less than or equal to α . For a… JEE Advanced 2026For the function f(x) = e^ |x| - |x| , x ∈ ℝ , consider the following statements… JEE Main 2026Let f(x) = cases (1)/(3), & x ≤ π/2 (b(1- x))/((π-2x)^2), & x > π/2 cases . If f is… JEE Main 2026Let f(x) = cases x^3 + 8 ; & x Then the number of points, where the function g ∘ f is… JEE Main 2026The number of points, at which the function f(x) = \ 6x, 2 + 3x^2\ + |x - 1|| |x^2… JEE Main 2026The number of points in the interval [2, 4] , at which the function f(x) = [x^2 - x… JEE Main 2026Let f(x)= _ θ arrow 0 ( π x-x^ ((2)/(θ)) (x-1) 1+x^ ((2)/(θ)) (x-1) ), x ∈ R . Consider… JEE Main 2026Let [t] denote the greatest integer less than or equal to t . If the function f(x)=\… JEE Main 2026If the function f(x)= e^ x (e^ x-x -1)+ _ e ( x+ x)-x x-x is continuous at x=0 , then the… JEE Main 2026Let α, β ∈ ℝ be such that the function f(x)= cases 2 α(x^ 2 -2)+2 β x &, x be… JEE Main 2026If f(x)=\ array cc a|x|+x^ 2 -2( |x|)( |x|) x &, x ≠ 0 b &, x=0 array . is continuous at… JEE Main 2026Let f(x)= cases a x^ 2 +2 a x+3 4 x^ 2 +4 x-3 &, x ≠-(3)/(2), (1)/(2) ~b &, x=-(3)/(2)… JEE Main 2026Let [·] denote the greatest integer function, and let f(x)= \ 2 x, x^ 2 \ . Let S = \ x… JEE Main 2026The number of points of discontinuity of the function f(x)=[ x^2 2 ]-[ x ], x ∈[0,4]… JEE Main 2025 Full Continuity and Differentiability list Continuity and Differentiability JEE Maths PYQsJEE Mathematics PYQs All JEE Main PYQs