Higher November 2023 Paper 4 Q17
17
(a) A sequence is defined by\[u_{n+1} = 3u_n + 7 \quad \text{and} \quad u_1 = -2.\]
Work out the value of \(u_2\) and the value of \(u_3\). [2]
(b) Here are the first four terms of a quadratic sequence.
\(-2 \qquad 7 \qquad 22 \qquad 43\)
The sequence has the formula \(x_n = an^2 + b\).
Find the value of \(a\) and the value of \(b\). [3]
| Answer | Marks | Part marks and guidance | |
|---|---|---|---|
| 1 | 1 | ||
| 10 | 1FT | FT from their 1 | |
| Answer | Marks | Part marks and guidance | |
|---|---|---|---|
| [\(a =\)] 3 [\(b =\)] −5 | 3 | B2 for [a =] 3 or B1 for [b =] −5 or M1 for second difference +6 or for a correct pair of simultaneous equations | e.g. \(a + b = -2\) and \(4a + b = 7\) |