1.

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

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)`


Discussion

No Comment Found

Related InterviewSolutions