| 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. Finding the common ratio from consecutive terms is direct division, finding the first term uses the nth term formula, and sum to infinity is a standard formula application. The final part requires calculating S_∞ - S_25 using the finite sum formula, which is slightly more involved but still routine C2 content with no novel 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 Q5 [10]}}