| Exam Board | CAIE |
| Module | FP1 (Further Pure Mathematics 1) |
| Year | 2016 |
| Session | November |
| Topic | Binomial Theorem (positive integer n) |
| Type | Standard binomial expansion |
4 Using factorials, show that \(\binom { n } { r - 1 } + \binom { n } { r } = \binom { n + 1 } { r }\).
Hence prove by mathematical induction that
$$( a + x ) ^ { n } = \binom { n } { 0 } a ^ { n } + \binom { n } { 1 } a ^ { n - 1 } x + \ldots + \binom { n } { r } a ^ { n - r } x ^ { r } + \ldots + \binom { n } { n } x ^ { n }$$
for every positive integer \(n\).