In the expansion of (1 – 3x + 3x2 – x3)2n, the middle term is (a) – InterviewSolution

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In the expansion of (1 – 3x + 3x2 – x3)2n, the middle term is (a) (n + 1)th term (b) (2n + 1)th term (c) (3n + 1)th term (d) None of these

Answer»

Answer : (c) (3n + 1)th term

(1 – 3x + 3x² – x³)²ⁿ = ((1 – x)³)²ⁿ = (1 – x)⁶ⁿ

^∴Middle term = \((\frac{6n}{2}+1)\)th term

= (3n+1)th term.

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