| Exam Board | OCR MEI |
|---|---|
| Module | C2 (Core Mathematics 2) |
| Year | 2010 |
| Session | June |
| Marks | 4 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Arithmetic Sequences and Series |
| Type | Sigma notation: direct numerical evaluation |
| Difficulty | Moderate -0.8 Part (i) is straightforward arithmetic evaluation of a simple sum (1/1 + 1/2 + 1/3 + 1/4). Part (ii) requires recognizing a pattern and expressing it in sigma notation, which is a standard C2 skill but requires minimal problem-solving. Both parts are routine exercises testing basic understanding of summation notation with no conceptual challenges. |
| Spec | 1.04g Sigma notation: for sums of series |
| Answer | Marks | Guidance |
|---|---|---|
| \(2\frac{1}{12}\) or \(\frac{25}{12}\) or \(2.08(3...)\) | 2 marks | B1 for \([1], \frac{1}{2}, \frac{1}{3}\) |
| Answer | Marks | Guidance |
|---|---|---|
| \(\sum_{r=2}^{6} r(r+1)\) o.e. | 2 marks | M1 for \([r(r+1)]\) o.e. or M1 for \([a]=6\) |
## (i)
$2\frac{1}{12}$ or $\frac{25}{12}$ or $2.08(3...)$ | 2 marks | B1 for $[1], \frac{1}{2}, \frac{1}{3}$
## (ii)
$\sum_{r=2}^{6} r(r+1)$ o.e. | 2 marks | M1 for $[r(r+1)]$ o.e. or M1 for $[a]=6$\begin{enumerate}[label=(\roman*)]
\item Evaluate $\sum_{r=2}^{5} \frac{1}{r-1}$. [2]
\item Express the series $2 \times 3 + 3 \times 4 + 4 \times 5 + 5 \times 6 + 6 \times 7$ in the form $\sum_{r=2}^{a} f(r)$ where $f(r)$ and $a$ are to be determined. [2]
\end{enumerate}
\hfill \mbox{\textit{OCR MEI C2 2010 Q2 [4]}}