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Consider the expansion `(x^(2)+(1)/(x))^(15)`. What is the independent term in the given expansion ?A. `""^(15)C_(9)`B. 0C. `-""^(15)C_(9)`D. 1 |
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Answer» Correct Answer - c Let `(r +1)^(th) ` term be the constant term in the expansion of `(x^(3) - (1)/(x^(2)))^(15)` . `because T_(r+1) = ""^(15)C_(r) (x^(3))^(15-r) (-(1)/(x^(2)))^(r)` is independent of x `rArr T_(r +1) = ""^(15)C_(r) x^(45 - 5r) (-1)^(r)` is independent of x `rArr 45 - 5r = 0 rArr r = 9` Thus , tenth is independent of x and is given by `T_(10) = ""^(15)C_(9) (-1)^(9) = - ""^(15)C_(9)` |
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