| Date | May 2010 | Marks available | 4 | Reference code | 10M.2.hl.TZ2.1 |
| Level | HL only | Paper | 2 | Time zone | TZ2 |
| Command term | Calculate, Find, and Write down | Question number | 1 | Adapted from | N/A |
Question
Consider the arithmetic sequence 8, 26, 44, \( \ldots \) .
(a) Find an expression for the \({n^{{\text{th}}}}\) term.
(b) Write down the sum of the first n terms using sigma notation.
(c) Calculate the sum of the first 15 terms.
Markscheme
(a) \(18n - 10\,\,\,\,\,\)(or equivalent) A1
(b) \(\sum\limits_1^n {(18r - 10)\,\,\,\,\,} \)(or equivalent) A1
(c) by use of GDC or algebraic summation or sum of an AP (M1)
\(\sum\limits_1^{15} {(18r - 10) = 2010} \) A1
[4 marks]
Examiners report
An easy starter question, but few candidates seem to be familiar with the conventions of sigma notation.
Syllabus sections
Topic 1 - Core: 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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