JEE Main 2025 — Continuity and Differentiability Question with Solution
JEE Main 2025 (3 Apr Shift 1)
Question
Let
be continuous at . Then is equal to
be continuous at . Then is equal to
Choose an option
Show full solutionCorrect option: C
Correct answer
C
Step-by-step explanation
$\begin{aligned}
& f\left(0^{-}\right)=\mathrm{e}^{\lim _{x \rightarrow 0} \frac{\mathrm{ax}}{\mathrm{x}}}=\mathrm{e}^{\mathrm{a}} \\ & \mathrm{f}(0)=1+\mathrm{b} \\ & \mathrm{f}\left(0^{+}\right)=\frac{\frac{1}{2 \sqrt{\mathrm{x}+4}}}{\frac{1}{3}(\mathrm{x}+\mathrm{c})^{-\frac{2}{3}}}=\frac{\frac{1}{2(2)}}{\frac{1}{3} \cdot \mathrm{c}^{-\frac{2}{3}}} \\ & =\frac{3}{4} \mathrm{c}^{2 / 3}
\end{aligned}\mathrm{x}=0c^{1 / 3}=2 \Rightarrow c=8\mathrm{f}\left(0^{+}\right)=\frac{3}{4}(8)^{2 / 3}=3\mathrm{e}^{\mathrm{a}}=\mathrm{b}+1=3\mathrm{e}^{\mathrm{a}} . \mathrm{b} \cdot \mathrm{c}=3 \cdot 2 \cdot 8=48$
& f\left(0^{-}\right)=\mathrm{e}^{\lim _{x \rightarrow 0} \frac{\mathrm{ax}}{\mathrm{x}}}=\mathrm{e}^{\mathrm{a}} \\ & \mathrm{f}(0)=1+\mathrm{b} \\ & \mathrm{f}\left(0^{+}\right)=\frac{\frac{1}{2 \sqrt{\mathrm{x}+4}}}{\frac{1}{3}(\mathrm{x}+\mathrm{c})^{-\frac{2}{3}}}=\frac{\frac{1}{2(2)}}{\frac{1}{3} \cdot \mathrm{c}^{-\frac{2}{3}}} \\ & =\frac{3}{4} \mathrm{c}^{2 / 3}
\end{aligned}\mathrm{x}=0c^{1 / 3}=2 \Rightarrow c=8\mathrm{f}\left(0^{+}\right)=\frac{3}{4}(8)^{2 / 3}=3\mathrm{e}^{\mathrm{a}}=\mathrm{b}+1=3\mathrm{e}^{\mathrm{a}} . \mathrm{b} \cdot \mathrm{c}=3 \cdot 2 \cdot 8=48$
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This is a previous-year question from JEE Main 2025, covering the Continuity and Differentiability chapter of Mathematics. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.