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AP EAMCET · Maths · Differentiation

\(f: R \rightarrow R\) is a function such that \(f(0)=1\) and for all \(x, y \in R f(x y+1)=f(x) f(y)-f(y)\), \(-x+2\), then \(\frac{d f}{d x}\) at \(x=e\) is

  1. A 0
  2. B -1
  3. C \(e\)
  4. D 1
Verified Solution

Answer & Solution

Correct Answer

(D) 1

Step-by-step Solution

Detailed explanation

Given functional relation is, \[ f(x y+1)=f(x) f(y)-f(y)-x+2 \] Now, put \(y=0\), then we are getting \[ \begin{gathered} f(\mathrm{l})=f(x) \cdot f(0)-f(0)-x+2 \\ \Rightarrow \quad f(\mathrm{l})=f(x)-1-x+2\{\because f(0)=1\} \end{gathered} \] On differentiating with respect to…