CUET · MATHS · PYQ PAPER 2025
If \(e^y(x+1)=1\) and \(\frac{d^2 y}{d x^2}=k\left(\frac{d y}{d x}\right)^2\), then \(k\) is equal to
- A -1
- B 1
- C 2
- D 3
Answer & Solution
Correct Answer
(B) 1
Step-by-step Solution
Detailed explanation
\(e^y(x+1)=1 \implies y = -\ln(x+1)\) \(\frac{dy}{dx} = -\frac{1}{x+1}\) \(\frac{d^2y}{dx^2} = -(-1)(x+1)^{-2}(1) = \frac{1}{(x+1)^2}\) \(\frac{1}{(x+1)^2} = k\left(-\frac{1}{x+1}\right)^2\) \(\frac{1}{(x+1)^2} = k\frac{1}{(x+1)^2}\) \(k = 1\)
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