| Exam Board | Edexcel |
|---|---|
| Module | C2 (Core Mathematics 2) |
| Marks | 8 |
| Paper | Download PDF ↗ |
| Topic | Standard trigonometric equations |
| Type | Convert to quadratic in sin/cos |
| Difficulty | Standard +0.3 This is a standard trigonometric equation requiring the Pythagorean identity to convert to a single function, then solving a quadratic in sin θ. While it involves multiple steps (substitution, factorization, finding angles in specified interval), these are routine C2 techniques with no novel insight required. The 8 marks reflect the working needed rather than conceptual difficulty, making it slightly easier than average. |
| Spec | 1.05j Trigonometric identities: tan=sin/cos and sin^2+cos^2=11.05o Trigonometric equations: solve in given intervals |
Find the values of $\theta$, to 1 decimal place, in the interval $-180 \leq \theta < 180$ for which
$$2 \sin^2 \theta ° - 2 \sin \theta ° = \cos^2 \theta °.$$ [8]
\hfill \mbox{\textit{Edexcel C2 Q14 [8]}}