Edexcel F1 2023 June — Question 1 4 marks

Exam BoardEdexcel
ModuleF1 (Further Pure Mathematics 1)
Year2023
SessionJune
Marks4
PaperDownload PDF ↗
TopicSequences and series, recurrence and convergence
TypeFinding constants from given sum formula
DifficultyStandard +0.3 This is a straightforward Further Maths question requiring algebraic manipulation of standard summation formulas. Students expand r²(r+2), apply known formulas for Σr² and Σr³, then factor to match the given form and identify constants by comparing coefficients—routine technique with no novel insight required.
Spec4.06a Summation formulae: sum of r, r^2, r^3

  1. Use the standard results for \(\sum _ { r = 1 } ^ { n } r ^ { 2 }\) and \(\sum _ { r = 1 } ^ { n } r ^ { 3 }\) to show that, for all positive integers \(n\)
$$\sum _ { r = 1 } ^ { n } r ^ { 2 } ( r + 2 ) = \frac { 1 } { 12 } n ( n + 1 ) \left( a n ^ { 2 } + b n + c \right)$$ where \(a\), \(b\) and \(c\) are integers to be determined.

\begin{enumerate}
  \item Use the standard results for $\sum _ { r = 1 } ^ { n } r ^ { 2 }$ and $\sum _ { r = 1 } ^ { n } r ^ { 3 }$ to show that, for all positive integers $n$
\end{enumerate}

$$\sum _ { r = 1 } ^ { n } r ^ { 2 } ( r + 2 ) = \frac { 1 } { 12 } n ( n + 1 ) \left( a n ^ { 2 } + b n + c \right)$$

where $a$, $b$ and $c$ are integers to be determined.

\hfill \mbox{\textit{Edexcel F1 2023 Q1 [4]}}