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 \begin{cases} e^{x-1}, & x<0 \\ x^2-5x+6, & x \geq 0 \end{cases}$g(x)=f(|x|)+|f(x)|g\alpha\beta\alpha+\beta$ is equal to ______
Correct answer
0
Step-by-step solution
We are given the function:
\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) = $\begin{cases} 2(x^2 - 5x + 6), & x \in (0, 2] \cup [3, \infty) \\ 0, & x \in (2, 3) \end{cases}
Differentiating for :
\begin{cases} 4x - 10, & x \in (0, 2) \cup (3, \infty) \\ 0, & x \in (2, 3) \end{cases}$x = 2g'(2^-) = 4(2) - 10 = -2g'(2^+) = 0g'(2^-) \neq g'(2^+)g(x)x = 2x = 3g'(3^-) = 0g'(3^+) = 4(3) - 10 = 2g'(3^-) \neq g'(3^+)g(x)x = 3g(x)x = 0, 2, 3\beta = 3\alpha + \beta = 1 + 3 = 44$
\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) = $\begin{cases} 2(x^2 - 5x + 6), & x \in (0, 2] \cup [3, \infty) \\ 0, & x \in (2, 3) \end{cases}
Differentiating for :
\begin{cases} 4x - 10, & x \in (0, 2) \cup (3, \infty) \\ 0, & x \in (2, 3) \end{cases}$x = 2g'(2^-) = 4(2) - 10 = -2g'(2^+) = 0g'(2^-) \neq g'(2^+)g(x)x = 2x = 3g'(3^-) = 0g'(3^+) = 4(3) - 10 = 2g'(3^-) \neq g'(3^+)g(x)x = 3g(x)x = 0, 2, 3\beta = 3\alpha + \beta = 1 + 3 = 44$