| Exam Board | Edexcel |
|---|---|
| Module | C2 (Core Mathematics 2) |
| Marks | 11 |
| Paper | Download PDF ↗ |
| Topic | Geometric Sequences and Series |
| Type | Find year when threshold exceeded |
| Difficulty | Moderate -0.3 This is a straightforward C2 geometric series question requiring standard formula applications. Part (a) uses sum to infinity formula (routine), parts (b-c) apply term and sum formulas directly, and part (d) requires solving an inequality but with given formulas. All techniques are standard textbook exercises with no novel problem-solving required, making it slightly easier than average. |
| Spec | 1.04i Geometric sequences: nth term and finite series sum1.04j Sum to infinity: convergent geometric series |r|<1 |
The first term of a geometric series is 120. The sum to infinity of the series is 480.
\begin{enumerate}[label=(\alph*)]
\item Show that the common ratio, $r$, is $\frac{3}{4}$.
[3]
\item Find, to 2 decimal places, the difference between the 5th and 6th terms.
[2]
\item Calculate the sum of the first 7 terms.
[2]
\end{enumerate}
The sum of the first $n$ terms of the series is greater than 300.
\begin{enumerate}[label=(\alph*)]
\setcounter{enumi}{3}
\item Calculate the smallest possible value of $n$.
[4]
\end{enumerate}
\hfill \mbox{\textit{Edexcel C2 Q4 [11]}}