| Date | November 2017 | Marks available | 2 | Reference code | 17N.1.sl.TZ0.2 |
| Level | SL only | Paper | 1 | Time zone | TZ0 |
| Command term | Find | Question number | 2 | Adapted from | N/A |
Question
In an arithmetic sequence, the first term is 8 and the second term is 5.
Find the common difference.
[2]
a.
Find the tenth term.
[2]
b.
Find the sum of the first ten terms.
[2]
c.
Markscheme
subtracting terms (M1)
eg\(\,\,\,\,\,\)\(5 - 8,{\text{ }}{u_2} - {u_1}\)
\(d = - 3\) A1 N2
[2 marks]
a.
correct substitution into formula (A1)
eg\(\,\,\,\,\,\)\({u_{10}} = 8 + (10 - 1)( - 3),{\text{ }}8 - 27,{\text{ }} - 3(10) + 11\)
\({u_{10}} = - 19\) A1 N2
[2 marks]
b.
correct substitution into formula for sum (A1)
eg\(\,\,\,\,\,\)\({S_{10}} = \frac{{10}}{2}(8 - 19),{\text{ 5}}\left( {2(8) + (10 - 1)( - 3)} \right)\)
\({S_{10}} = - 55\) A1 N2
[2 marks]
c.
Examiners report
[N/A]
a.
[N/A]
b.
[N/A]
c.
Syllabus sections
Topic 1 - Algebra » 1.1 » Arithmetic sequences and series; sum of finite arithmetic series; geometric sequences and series; sum of finite and infinite geometric series.
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