| Exam Board | WJEC |
|---|---|
| Module | Further Unit 4 (Further Unit 4) |
| Year | 2023 |
| Session | June |
| Marks | 6 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Standard trigonometric equations |
| Type | General solution — find all solutions |
| Difficulty | Challenging +1.2 This is a Further Maths trigonometric equation requiring multiple-angle formula application (cos 4θ = 2cos²2θ - 1, cos 2θ = 2cos²θ - 1) and factorization to solve. While it involves several algebraic steps and substitution, the techniques are standard for Further Maths students, making it moderately above average difficulty but not requiring novel insight. |
| Spec | 1.05l Double angle formulae: and compound angle formulae1.05o Trigonometric equations: solve in given intervals |
Find the general solution of the equation
$$\cos 4\theta + \cos 2\theta = \cos\theta.$$ [6]
\hfill \mbox{\textit{WJEC Further Unit 4 2023 Q12 [6]}}