| Exam Board | OCR MEI |
|---|---|
| Module | C2 (Core Mathematics 2) |
| Year | 2015 |
| Session | June |
| Marks | 5 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Quadratic trigonometric equations |
| Type | Show then solve: sin²/cos² substitution |
| Difficulty | Moderate -0.3 This is a standard textbook exercise requiring the identity sin²x = 1 - cos²x to convert to a quadratic, then routine factorization and solving. The technique is well-practiced in C2, making it slightly easier than average, though the multi-step nature and range restriction prevent it from being trivial. |
| Spec | 1.05j Trigonometric identities: tan=sin/cos and sin^2+cos^2=11.05o Trigonometric equations: solve in given intervals |
7 Show that the equation $\sin ^ { 2 } x = 3 \cos x - 2$ can be expressed as a quadratic equation in $\cos x$ and hence solve the equation for values of $x$ between 0 and $2 \pi$.
\hfill \mbox{\textit{OCR MEI C2 2015 Q7 [5]}}