| Date | November 2012 | Marks available | 2 | Reference code | 12N.2.sl.TZ0.1 |
| Level | SL only | Paper | 2 | Time zone | TZ0 |
| Command term | Find | Question number | 1 | Adapted from | N/A |
Question
The first three terms of an arithmetic sequence are 5 , 6.7 , 8.4 .
Find the common difference.
The first three terms of an arithmetic sequence are 5 , 6.7 , 8.4 .
Find the 28th term of the sequence.
The first three terms of an arithmetic sequence are \(5\) , \(6.7\) , \(8.4\) .
Find the sum of the first 28 terms.
Markscheme
valid method (M1)
e.g. subtracting terms, using sequence formula
\(d = 1.7\) A1 N2
[2 marks]
correct substitution into term formula (A1)
e.g. \(5 + 27(1.7)\)
28th term is 50.9 (exact) A1 N2
[2 marks]
correct substitution into sum formula (A1)
e.g. \({S_{28}} = \frac{{28}}{2}(2(5) + 27(1.7))\) , \(\frac{{28}}{2}(5 + 50.9)\)
\({S_{28}} = 782.6\) (exact) [\(782\), \(783\)] A1 N2
[2 marks]
Examiners report
Most candidates performed well on this question. A few were confused between the term number and the value of a term.
Most candidates performed well on this question. A few were confused between the term number and the value of a term.
Most candidates performed well on this question. A few were confused between the term number and the value of a term.
