Answer: n+1.
- A n
- B n-1
- C n+1
- D 2n
Correct answer: C. n+1
Explanation: The expansion has terms T<sub>1</sub>, T<sub>2</sub>, ..., T(n+1), so n+1 terms total.
Row n of Pascal's triangle gives the coefficients nC0, nC1, ..., nCn for the expansion of (a+b)ⁿ; each number is the sum of the two numbers diagonally above it, a direct visual proof of the identity nCr = (n-1)C(r-1) + (n-1)Cr.
Concept context
Expansion of (a+b) n , general term, middle term, binomial coefficients, and greatest term