Higher November 2024 Paper 2 Q20
20 Here is a formula for an iterative process.
\[u_{n + 1} = \dfrac{24}{u_n} + 4\]\(u_2 = 8\)
Work out the values of \(\quad u_1\) and \(u_3\) [3 marks]
| Answer | Mark | Comments |
|---|---|---|
| \(8 = \dfrac{24}{u_1} + 4\) | M1 | oe eg \(4 = \dfrac{24}{u_1}\) accept \(u_1\) replaced by a different variable eg \(x\) |
| \(u_1 = 6\) | A1 | do not accept \(x = 6\) in working with nothing on answer line for \(u_1\) |
| \(u_3 = 7\) | B1 | SC1 \(u_1 = 7\) and \(u_3 = 7\dfrac{3}{7}\) or \(\dfrac{52}{7}\) or [7.4, 7.43] or \(u_1 = 7\) and \(u_3 = 7\dfrac{3}{13}\) or \(\dfrac{94}{13}\) or [7.2, 7.231] |
Additional guidance
| M1 may be awarded for correct work with no answer or incorrect answer, even if this is seen amongst multiple attempts | |
| Embedded \(u_1\) eg \(8 = \dfrac{24}{6} + 4\) | M1 |