| Exam Board | OCR |
|---|---|
| Module | H240/03 (Pure Mathematics and Mechanics) |
| Marks | 4 |
| Paper | Download PDF ↗ |
| Topic | Trig Graphs & Exact Values |
| Type | Solve trigonometric equation to find exact trigonometric ratio |
| Difficulty | Standard +0.8 This question requires using the double angle formula (sin 2x = 2sin x cos x), rearranging to form a quadratic in sin x or cos x, and solving to find an exact value. While it involves multiple steps and the double angle identity, it's a fairly standard technique taught in A-level. The constraint to exact values and the need to manipulate the equation elevates it slightly above average difficulty, but it remains a recognizable problem type that students practice regularly. |
| Spec | 1.05j Trigonometric identities: tan=sin/cos and sin^2+cos^2=11.05l Double angle formulae: and compound angle formulae1.05o Trigonometric equations: solve in given intervals |
3 In this question you must show detailed reasoning.
Given that $5 \sin 2 x = 3 \cos x$, where $0 ^ { \circ } < x < 90 ^ { \circ }$, find the exact value of $\sin x$.
\hfill \mbox{\textit{OCR H240/03 Q3 [4]}}