| Exam Board | Edexcel |
|---|---|
| Module | C2 (Core Mathematics 2) |
| Marks | 10 |
| Paper | Download PDF ↗ |
| Topic | Geometric Sequences and Series |
| Type | Find sum to infinity |
| Difficulty | Moderate -0.8 This is a straightforward C2 geometric series question requiring only standard formula application. Parts (a)-(c) involve direct use of basic GP formulas (r = u₄/u₃, finding u₁, and S∞), while part (d) requires calculating S₂₅ and finding a difference. All steps are routine with no problem-solving insight needed, making it easier than average but not trivial due to the multi-part structure and arithmetic involved. |
| 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 Q3 [10]}}