| Date | May 2016 | Marks available | 2 | Reference code | 16M.2.sl.TZ2.1 |
| Level | SL only | Paper | 2 | Time zone | TZ2 |
| Command term | Find | Question number | 1 | Adapted from | N/A |
Question
The first three terms of an arithmetic sequence are \({u_1} = 0.3,{\text{ }}{u_2} = 1.5,{\text{ }}{u_3} = 2.7\).
Find the common difference.
Find the 30th term of the sequence.
Find the sum of the first 30 terms.
Markscheme
valid approach (M1)
eg\(\,\,\,\,\,\)\(1.5 - 0.3,{\text{ }}1.5 - 2.7,{\text{ }}2.7 = 0.3 + 2d\)
\(d = 1.2\) A1 N2
[2 marks]
correct substitution into term formula (A1)
eg\(\,\,\,\,\,\)\(0.3 + 1.2(30 - 1),{\text{ }}{u_{30}} = 0.3 + 29(1.2)\)
\({u_{30}} = 35.1\) A1 N2
[2 marks]
correct substitution into sum formula (A1)
eg\(\,\,\,\,\,\)\({S_{30}} = \frac{{30}}{2}(0.3 + 35.1),{\text{ }}\frac{{30}}{2}\left( {2(0.3) + 29(1.2)} \right)\)
\({S_{30}} = 531\) A1 N2
[2 marks]
Examiners report
Most candidates found this question straightforward and accessible. They could find the correct difference and substituted correctly into term and sum formula respectively.
Most candidates found this question straightforward and accessible. They could find the correct difference and substituted correctly into term and sum formula respectively.
Most candidates found this question straightforward and accessible. They could find the correct difference and substituted correctly into term and sum formula respectively.
