| Exam Board | OCR MEI |
|---|---|
| Module | C2 (Core Mathematics 2) |
| Marks | 4 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Arithmetic Sequences and Series |
| Type | Sigma notation: direct numerical evaluation |
| Difficulty | Easy -1.3 Part (i) is direct substitution into sigma notation requiring only basic fraction arithmetic. Part (ii) involves pattern recognition to express a simple series in sigma notation, which is a routine C2 skill. Both parts are straightforward exercises with no problem-solving or conceptual depth required. |
| 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 | M1 for \(\frac{1}{1} + \frac{1}{2} + \frac{1}{3} + \frac{1}{4}\) |
| Answer | Marks | Guidance |
|---|---|---|
| \(\sum_{r=2}^{6} r(r+1)\) oe | 2 | M1 for \([\text{f}(r) =] r(r+1)\) oe; M1 for \([a =] 6\) |
## Question 7(i):
| $2\frac{1}{12}$ or $\frac{25}{12}$ or $2.08(3...)$ | 2 | **M1** for $\frac{1}{1} + \frac{1}{2} + \frac{1}{3} + \frac{1}{4}$ |
## Question 7(ii):
| $\sum_{r=2}^{6} r(r+1)$ oe | 2 | **M1** for $[\text{f}(r) =] r(r+1)$ oe; **M1** for $[a =] 6$ |7\\
(i) Evaluate $\sum _ { r = 2 } ^ { 5 } \frac { 1 } { r - 1 }$.\\
(ii) Express the series $2 \times 3 + 3 \times 4 + 4 \times 5 + 5 \times 6 + 6 \times 7$ in the form $\sum _ { r = 2 } ^ { a } \mathrm { f } ( r )$ where $\mathrm { f } ( r )$ and $a$ are to be determined.
\hfill \mbox{\textit{OCR MEI C2 Q7 [4]}}