| Exam Board | WJEC |
|---|---|
| Module | Unit 3 (Unit 3) |
| Year | 2018 |
| Session | June |
| Marks | 6 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Newton-Raphson method |
| Type | Newton-Raphson with trigonometric or exponential functions |
| Difficulty | Moderate -0.3 This is a straightforward application of standard techniques: sketching two simple graphs (y=x-1 and y=cos x) to show intersection, then applying the Newton-Raphson formula mechanically with a given starting value. The graphical part requires minimal insight, and the iterative calculation is routine bookwork requiring 2-3 iterations to reach 2 d.p. accuracy. Slightly easier than average due to the prescribed method and starting value. |
| Spec | 1.02q Use intersection points: of graphs to solve equations1.09d Newton-Raphson method |
By drawing suitable graphs, show that $x - 1 = \cos x$ has only one root. Starting with $x_0 = 1$, use the Newton-Raphson method to find the value of this root correct to two decimal places. [6]
\hfill \mbox{\textit{WJEC Unit 3 2018 Q17 [6]}}