Foundation November 2022 Paper 2 Q20
20 Here are the first five terms of an arithmetic sequence.
\[7 \qquad 13 \qquad 19 \qquad 25 \qquad 31\](a) Find an expression, in terms of \(n\), for the \(n\)th term of this sequence. (2)
The \(n\)th term of a different sequence is \(\;8 - 6n\)
(b) Is \(\;-58\) a term of this sequence?
You must show how you get your answer. (2)
You must show how you get your answer. (2)
| Answer | Mark | Mark scheme |
|---|---|---|
| \(6n + 1\) | B2 | oe |
| (B1 | for \(6n + c\) where \(c\) is an integer \(\neq 1\) or is missing) |
| Answer | Mark | Mark scheme |
|---|---|---|
| Shown with supportive working | M1 | for \(8 - 6n = -58\) or \(8 - 6 \times 11\ (= -58)\) or starts to list terms of the sequence, with at least 3 correct or any other valid method. |
| A1 | shown with working or an explanation, eg Yes and 11 or \(2, -4, -10, -16, ......, -52, -58\) |
Additional guidance
\(2, -4, -10, -16, -22, -28, -34, -40, -46, -52\)
May stop at \(-58\) or ring if sequence continues