Higher June 2023 Paper 2R Q4
4 Here are the first four terms of an arithmetic sequence.
38 31 24 17
Find an expression, in terms of \(n\), for the \(n\)th term of the sequence.
(2)
| Scheme | Marks |
|---|---|
| M1 | |
| Correct answer scores full marks (unless from obvious incorrect working) Answer: \(45 - 7n\) | A1 |
| (2) | |
| (2 marks) |
Notes
M1: for \(-7n + k\;(k \ne 45)\) or
\(-7 \times n + k\;(k \ne 45)\) or
\(n \times -7 + k\;(k \ne 45)\)
(\(k\) may be zero or absent or negative)
A1: oe
eg \(45 - 7 \times n\) oe or
\(-7 \times n + 45\) oe or
\(U_n = 45 - 7n\) oe or
\(38 - 7(n - 1)\) oe
NB: award full marks for eg
\(x = 45 - 7n\) oe or
\(n\)th term \(= -7 \times n + 45\) oe or
but only M1 for \(n = 45 - 7n\) oe