| Exam Board | OCR MEI |
|---|---|
| Module | C4 (Core Mathematics 4) |
| Paper | Download PDF ↗ |
| Topic | Solving quadratics and applications |
| Type | Quadratic with surd roots, exact form |
| Difficulty | Standard +0.8 This requires algebraic manipulation of the golden ratio φ = (√5+1)/2 to show its reciprocal equals (√5-1)/2. Students must rationalize the denominator or use φ² = φ+1, requiring insight beyond routine rearrangement and careful algebraic handling of surds. |
| Spec | 1.02b Surds: manipulation and rationalising denominators |
5 Justify the statement in line 87 that
$$\frac { 1 } { \phi } = \frac { \sqrt { 5 } - 1 } { 2 }$$
\hfill \mbox{\textit{OCR MEI C4 Q5}}