Answer: 1.
- A 1
- B 2
- C 10
- D 32
Correct answer: A. 1
Explanation: Coefficient of x<sup>5</sup> in (2+x)<sup>5</sup>: T<sub>6</sub> = 5C5 x 2<sup>0</sup> x x<sup>5.</sup> Coefficient = 5C5 x 1 = 1.
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