| Exam Board | OCR MEI |
|---|---|
| Module | C2 (Core Mathematics 2) |
| Marks | 5 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Arithmetic Sequences and Series |
| Type | Sequence defined by formula |
| Difficulty | Moderate -0.8 This is a straightforward question requiring basic substitution to find terms and applying the standard arithmetic series formula. Part (i) is trivial substitution, and part (ii) is a direct application of the sum formula for an arithmetic sequence with no problem-solving required—easier than average but not completely trivial. |
| Spec | 1.04e Sequences: nth term and recurrence relations1.04g Sigma notation: for sums of series |
| Answer | Marks | Guidance |
|---|---|---|
| (i) Values calculated \(6, 11, 16, \ldots\) | B1 | Total: 1 mark |
| (ii) Identify \(a = 6, d = 5\) | M1, A1 | Both |
| \(S_{100} = \frac{100}{2}(2(6) + 99(5))\) | M1 | |
| \(= 25350\) | A1 | Total: 4 marks |
**(i)** Values calculated $6, 11, 16, \ldots$ | B1 | **Total: 1 mark**
**(ii)** Identify $a = 6, d = 5$ | M1, A1 | Both
$S_{100} = \frac{100}{2}(2(6) + 99(5))$ | M1 |
$= 25350$ | A1 | **Total: 4 marks**5 A sequence is defined by $a _ { k } = 5 k + 1$, for $k = 1,2,3 \ldots$\\
(i) Write down the first three terms of the sequence.\\
(ii) Evaluate $\sum _ { k = 1 } ^ { 100 } a _ { k }$.
\hfill \mbox{\textit{OCR MEI C2 Q5 [5]}}