| Exam Board | OCR MEI |
|---|---|
| Module | C1 (Core Mathematics 1) |
| Year | 2009 |
| Session | June |
| Marks | 4 |
| Paper | Download PDF ↗ |
| Topic | Completing the square and sketching |
| Type | Solve quartic as quadratic |
| Difficulty | Moderate -0.3 This is a standard quadratic-in-disguise problem requiring substitution u=x², solving the resulting quadratic, then taking square roots. It's slightly easier than average because the technique is explicitly prompted ('considering it as a quadratic equation in x²') and the numbers factor cleanly (u²-5u-36 = (u-9)(u+4)), requiring only basic algebraic manipulation. |
| Spec | 1.02f Solve quadratic equations: including in a function of unknown |
Find the real roots of the equation $x^4 - 5x^2 - 36 = 0$ by considering it as a quadratic equation in $x^2$. [4]
\hfill \mbox{\textit{OCR MEI C1 2009 Q10 [4]}}