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WBJEE · Maths · Differentiation

If \(y=(1+x)\left(1+x^{2}\right)\left(1+x^{4}\right) \ldots\left(1+x^{2 n}\right),\) then the value of \(\left(\frac{d y}{d x}\right)\) at \(x=0\) is

  1. A 0
  2. B -1
  3. C 1
  4. D 2
Verified Solution

Answer & Solution

Correct Answer

(C) 1

Step-by-step Solution

Detailed explanation

Given, \(y=(1+x)\left(1+x^{2}\right)\left(1+x^{4}\right)+\ldots+\left(1+x^{2 n}\right)\) \(\Rightarrow \log y=\log (1+x)+\log \left(1+x^{2}\right)\) \(+\log \left(1+x^{4}\right)+\ldots+\log \left(1+x^{2n}\right)\)…