| Exam Board | WJEC |
|---|---|
| Module | Unit 3 (Unit 3) |
| Year | 2019 |
| Session | June |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Generalised Binomial Theorem |
| Type | Product with linear term |
| Difficulty | Standard +0.8 This question requires applying the binomial expansion to (1+2x)^(-1/2), multiplying by (4-x), collecting terms up to x³, and determining the validity condition |2x|<1. It combines multiple algebraic steps with understanding of convergence, making it moderately challenging but still a standard Further Maths exercise. |
| Spec | 1.04c Extend binomial expansion: rational n, |x|<11.04d Binomial expansion validity: convergence conditions |
Expand $\frac { 4 - x } { \sqrt { 1 + 2 x } }$ in ascending powers of $x$ up to and including the term in $x ^ { 3 }$. State the range of values of $x$ for which the expansion is valid.
\hfill \mbox{\textit{WJEC Unit 3 2019 Q2}}