Higher November 2023 Paper 3 Q14
14 Here are the first six terms of a quadratic sequence.
\[5 \qquad 11 \qquad 21 \qquad 35 \qquad 53 \qquad 75\]Find an expression, in terms of \(n\), for the \(n\)th term of this sequence. (2)
| Answer | Mark | Mark scheme |
|---|---|---|
| \(2n^2 + 3\) | M1 | for a correct start to a method to find the \(n\)th term eg constant 2nd differences of 4 and the term \(2n^2\) or states \(an^2 + bn + c\) (where \(bn\) may be missing) and \(2a = 4\) or gives the sequence 2, 8, 18, … |
| A1 | oe |
Additional guidance
Need to see constant second difference found and \(2n^2\)
Condone use of different variable throughout