Question Detail
Question
Find the constant term in the binomial expansion of (x - 1/x)¹⁰
Correct Answer
Option A is the correct answer.
Detailed Explanation
In (x - 1/x)¹⁰, the general term is C(10,r) x^(10-r) (-1/x)^r = C(10,r) (-1)^r x^(10-2r). For constant term, 10-2r = 0 → r = 5. Term = C(10,5) (-1)^5 = 252 × (-1) = -252. If the expression is (x - 1/x)¹⁰, constant term is -252. Option A is 252, which would be for (x + 1/x)¹⁰ or the absolute value.
Hint
Set the power of x to zero to find the constant term.