If n is odd number, then middle term in expansion (a + x)^n is:
Correct answer: D. (n+1)/2 and (n+3)/2
- A. (n+1)/2
- B. (n+3)/2
- C. (n-1)/2
- D. (n+1)/2 and (n+3)/2
Explanation
When n is an odd number, the expansion of (a + x)^n has two middle terms.The general term in the expansion of (a + x)^n is given by:(n choose r) a^(n-r) x^rThe middle terms occur when r = (n-1)/2 and r = (n+1)/2.Substituting these values of r, we get the middle terms as:(n choose (n-1)/2) a^(n-(n-1)/2) x^(n-1)/2(n choose (n+1)/2) a^(n-(n+1)/2) x^(n+1)/2
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