Higher November 2019 Paper 3 Q20
20 Here are the first five terms of a sequence.
\(-1 \qquad 0 \qquad 3 \qquad 8 \qquad 15\)
Find an expression, in terms of \(n\), for the \(n\)th term of this sequence. (2)
| Answer | Mark | Mark scheme |
|---|---|---|
| \(n^2 - 2n\) | M1 | for correct deduction from differences, eg 2nd difference of 2 implies \(1n^2\) or gives a quadratic expression which includes the term \(1n^2\) or states 1, 4, 9, 16, 25 and deduces 2, 4, 6, 8, 10 |
| A1 | oe |