Binomial TheoremHard
Question
Given that the term of the expansion (x1/3 - x-1/2)15 which does not contain x is 5 m, where m ∈ N,then m =
Options
A.1100
B.1010
C.1001
D.none
Solution
(x1/3 - x-1/2)15
Tr+1 = 15Cr
(-x-1/2)r
For constant term
= 0 ⇒ r = 6
Co-efficient of x0 = 15C6 = 5 × 1001 ⇒ m = 1001
Tr+1 = 15Cr
(-x-1/2)r For constant term
= 0 ⇒ r = 6 Co-efficient of x0 = 15C6 = 5 × 1001 ⇒ m = 1001
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