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AP EAMCET · Maths · Binomial Theorem

If \(|x| \lt 1\), then the number of terms in the expansion of \(\left[\frac{1}{2}\left(1.2+2.3 x+3.4 x^2+\ldots . . \infty\right)\right]^{-25}\) is

  1. A Infinite
  2. B 101
  3. C 76
  4. D 51
Verified Solution

Answer & Solution

Correct Answer

(C) 76

Step-by-step Solution

Detailed explanation

\(\because(1-x)^{-1}=1+x+x^2+x^3+x^4+\ldots \infty\) Differentiate w.r.t. \(x\) \((1-x)^{-2}=1+2 x+3 x^2+4 x^3+\ldots \infty\) Differentiate again w.r.t. \(x\)…