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JEE Mains · Maths · STD 11 - 7. binomial theoram

यदि गुणनफल \(\left(1+ x + x ^{2}+\ldots+ x ^{2 n }\right)\left(1- x + x ^{2}\right.\) \(\left.- x ^{3}+\ldots+ x ^{2 n }\right)\) में, \(x\) के सभी सम-घातों वाले गुणाकों का योगफल \(61\) है, तो \(n\) बराबर ....... है |

  1. A \(30\)
  2. B \(26\)
  3. C \(22\)
  4. D \(20\)
Verified Solution

Answer & Solution

Correct Answer

(A) \(30\)

Step-by-step Solution

Detailed explanation

Let \(\left(1+x+x^{2}+\ldots+x^{2 n}\right)\left(1-x+x^{2}-x^{3}+\ldots+x^{2 n}\right)\) \(=a_{0}+a_{1} x_{+} a_{2} x^{2}+a_{3} x^{3}+a_{4} x^{4}+\ldots+a_{4 n} x^{4 n}\) \(\mathrm{So}\) \(a_{0}+a_{1}+a_{2}+\ldots+a_{4 n}=2 n+1\) \(a_{0}-a_{1}+a_{2}-a_{3} \ldots+a_{4 n}=2 n+1\)…
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