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AP EAMCET · Maths · Binomial Theorem

If \({ }^{(n-1)} C_r=\left(k^2-3\right){ }^n C_{r+1}\), then an interval containing the values of \(k\), is

  1. A \((-\infty,-3]\)
  2. B \([-2,-\sqrt{3})\)
  3. C \([-\sqrt{3}, \sqrt{3}]\)
  4. D \((-\infty,-\sqrt{2}]\)
Verified Solution

Answer & Solution

Correct Answer

(B) \([-2,-\sqrt{3})\)

Step-by-step Solution

Detailed explanation

\( \frac{(n-1)!}{r!(n-r-1)!} = (k^2-3) \frac{n!}{(r+1)!(n-r-1)!} \) \( 1 = (k^2-3) \frac{n}{r+1} \) \( k^2-3 = \frac{r+1}{n} \) For combinations to be defined, \( n \ge r+1 \) and \( r \ge 0 \). Thus, \( 1 \le r+1 \le n \), implying \( 0 \( 0…