Edexcel FP1 — Question 16 6 marks

Exam BoardEdexcel
ModuleFP1 (Further Pure Mathematics 1)
Marks6
PaperDownload PDF ↗
TopicSequences and series, recurrence and convergence
TypeStandard summation formulae application
DifficultyStandard +0.3 This is a straightforward summation question requiring expansion of the product, application of standard summation formulas (Σr and Σr²), and algebraic manipulation to reach the given result. Part (b) is routine substitution. While it requires careful algebra, it's a standard FP1 exercise with no novel insight needed—slightly easier than average A-level difficulty.
Spec4.06a Summation formulae: sum of r, r^2, r^34.06b Method of differences: telescoping series

  1. Show that \(\sum_{r=1}^{n} (r + 1)(r + 5) = \frac{1}{6} n(n + 7)(2n + 7)\). [4]
  2. Hence calculate the value of \(\sum_{r=10}^{40} (r + 1)(r + 5)\). [2]

\begin{enumerate}[label=(\alph*)]
\item Show that $\sum_{r=1}^{n} (r + 1)(r + 5) = \frac{1}{6} n(n + 7)(2n + 7)$. [4]
\item Hence calculate the value of $\sum_{r=10}^{40} (r + 1)(r + 5)$. [2]
\end{enumerate}

\hfill \mbox{\textit{Edexcel FP1  Q16 [6]}}