| Exam Board | Edexcel |
|---|---|
| Module | C2 (Core Mathematics 2) |
| Marks | 10 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Geometric Sequences and Series |
| Type | Find sum to infinity |
| Difficulty | Moderate -0.3 This is a straightforward geometric series question requiring standard formulas and procedures. Parts (a)-(c) involve direct application of GP formulas (finding r from consecutive terms, working backwards to find a, then using S_∞ = a/(1-r)). Part (d) requires calculating S_25 and subtracting, which is slightly more involved but still routine. The question is slightly easier than average because it's entirely procedural with no conceptual challenges or problem-solving required. |
| Spec | 1.04i Geometric sequences: nth term and finite series sum1.04j Sum to infinity: convergent geometric series |r|<1 |
The third and fourth terms of a geometric series are 6.4 and 5.12 respectively.
Find
\begin{enumerate}[label=(\alph*)]
\item the common ratio of the series, [2]
\item the first term of the series, [2]
\item the sum to infinity of the series. [2]
\item Calculate the difference between the sum to infinity of the series and the sum of the first 25 terms of the series. [4]
\end{enumerate}
\hfill \mbox{\textit{Edexcel C2 Q6 [10]}}