JEE Main 2025MathematicsDeterminantsMediumMCQ

JEE Main 2025Determinants Question with Solution

JEE Main 2025 (24 Jan Shift 2)

Question

For some , let . Then is equal to :

Choose an option

Show full solutionCorrect option: A
Correct answer
A16

Step-by-step explanation

$\lim _{x \rightarrow 0}\left|\begin{array}{ccc} a+\frac{\sin x}{x} & 1 & b \\ a & 1+\frac{\sin x}{x} & b \\ a & 1 & b+\frac{\sin x}{x} \end{array}\right|=\lambda+\mu a+v b$ At , $\begin{aligned} & f(x)=\left|\begin{array}{ccc} a+1 & 1 & b \\ a & 1+1 & b \\ a & 1 & b+1 \end{array}\right|=\lambda+\mu a+v b \\ & R_1 \rightarrow R_1-R_2 \\ & R_2 \rightarrow R_2-R_3 \\ & \left|\begin{array}{ccc} 1 & -1 & 0 \\ 0 & 1 & -1 \\ a & 1 & b+1 \end{array}\right|=\lambda+\mu a+v b \\ & \mathrm{C}_2 \rightarrow \mathrm{C}_1-\mathrm{C}_2 \\ & \left|\begin{array}{ccc} 1 & 0 & 0 \\ 0 & 1 & -1 \\ a & a+1 & b+1 \end{array}\right|=\lambda+\mu a+v b \\ & a+b+2=\lambda+\mu a+v b \\ & \lambda=2, \mu=1, \quad v=1 \\ & (\lambda+\mu+v)=(2+1+1)^2=16 \end{aligned}$

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About this question

This is a previous-year question from JEE Main 2025, covering the Determinants 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.