| Exam Board | OCR |
|---|---|
| Module | C2 (Core Mathematics 2) |
| Marks | 4 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Geometric Sequences and Series |
| Type | Sum of first n terms |
| Difficulty | Moderate -0.8 This is a straightforward application of the geometric series formula with clearly identified first term (a=10) and common ratio (r=2). It requires only direct substitution into the standard formula S_n = a(r^n - 1)/(r - 1), making it easier than average with minimal problem-solving needed. |
| Spec | 1.04g Sigma notation: for sums of series1.04i Geometric sequences: nth term and finite series sum |
\begin{enumerate}
\item Evaluate
\end{enumerate}
$$\sum _ { r = 1 } ^ { 12 } \left( 5 \times 2 ^ { r } \right)$$
\hfill \mbox{\textit{OCR C2 Q1 [4]}}