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TS EAMCET · Maths · Binomial Theorem

If the coefficients of \((2 r+1)^{\text {th }}\) term and \((r+1)^{\text {th }}\) term in the expansion of \((1+x)^{42}\) are equal then \(r\) can be

  1. A 12
  2. B 14
  3. C 16
  4. D 20
Verified Solution

Answer & Solution

Correct Answer

(B) 14

Step-by-step Solution

Detailed explanation

We have, \((1+x)^{42}\) \[ \begin{gathered} T_{2 r+1}={ }^{42} C_{2 r} x^{2 r} \\ T_{r+1}={ }^{42} C_r x^r \end{gathered} \] Coefficient of \((2 r+1)^{\text {th }}\) and \((r+1)^{\text {th }}\) term are equal…