| Exam Board | Edexcel |
|---|---|
| Module | C2 (Core Mathematics 2) |
| Marks | 8 |
| Paper | Download PDF ↗ |
| Topic | Geometric Sequences and Series |
| Type | Find common ratio from terms |
| Difficulty | Moderate -0.3 This is a straightforward geometric series question requiring standard formulas and calculator work. Parts (a) and (b) involve basic algebraic manipulation (finding r from ar³/ar = 5.832/7.2, then finding a), while parts (c) and (d) are direct applications of sum formulas. The multi-part structure adds some length, but each step is routine with no conceptual challenges or problem-solving insight required—slightly easier than the average A-level question. |
| Spec | 1.04i Geometric sequences: nth term and finite series sum1.04j Sum to infinity: convergent geometric series |r|<1 |
The second and fourth terms of a geometric series are 7.2 and 5.832 respectively.
The common ratio of the series is positive.
For this series, find
\begin{enumerate}[label=(\alph*)]
\item the common ratio,
[2]
\item the first term,
[2]
\item the sum of the first 50 terms, giving your answer to 3 decimal places,
[2]
\item the difference between the sum to infinity and the sum of the first 50 terms, giving your answer to 3 decimal places.
[2]
\end{enumerate}
\hfill \mbox{\textit{Edexcel C2 Q6 [8]}}