Consider the expansion of (1+x)^n. Let p, q, r and s be the coefficients of first, second, nth and (n+1)th terms respectively. What is (ps+qr) equal to?

NDA 2021 Mathematics question

Consider the expansion of . Let , , and be the coefficients of first, second, th and th terms respectively. What is equal to?

Answer: (C)

The th term of is . So , , (coefficient of the th term) and

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Question ID VK-033638