| Exam Board | OCR |
|---|---|
| Module | C3 (Core Mathematics 3) |
| Marks | 6 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Reciprocal Trig & Identities |
| Type | Solve equation with reciprocal functions |
| Difficulty | Standard +0.3 This requires converting cosec to 1/sin, multiplying through to get a quadratic in sin θ, then solving and applying CAST diagram within a restricted domain. It's slightly above average due to the reciprocal function manipulation and quadratic solving, but follows a standard C3 procedure with no novel insight required. |
| Spec | 1.05h Reciprocal trig functions: sec, cosec, cot definitions and graphs1.05o Trigonometric equations: solve in given intervals |
2. Solve the equation
$$3 \operatorname { cosec } \theta ^ { \circ } + 8 \cos \theta ^ { \circ } = 0$$
for $\theta$ in the interval $0 \leq \theta \leq 180$, giving your answers to 1 decimal place.\\
\hfill \mbox{\textit{OCR C3 Q2 [6]}}