AQA Paper 1 2019 June — Question 8 4 marks

Exam BoardAQA
ModulePaper 1 (Paper 1)
Year2019
SessionJune
Marks4
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicArithmetic Sequences and Series
TypeStandard summation formula application
DifficultyStandard +0.3 This question tests telescoping series and recognizing that P(n) = n³. Part (a) is straightforward calculation, while part (b) requires taking a cube root. The conceptual insight that the difference of consecutive sums equals the last term is standard, and the arithmetic is routine, making this slightly easier than average.
Spec1.04g Sigma notation: for sums of series

$$P(n) = \sum_{k=0}^{n} k^3 - \sum_{k=0}^{n-1} k^3 \text{ where } n \text{ is a positive integer.}$$
  1. Find P(3) and P(10) [2 marks]
  2. Solve the equation \(P(n) = 1.25 \times 10^8\) [2 marks]

Question 8:

AnswerMarks Guidance
8(a)Obtains one correct value 1.1b
P 3
( )=1000
P 10
AnswerMarks Guidance
Obtains both correct values1.1b B1

AnswerMarks
8(b)Forms cubic equation replacing
P ( n )=n3 (condone k3)
AnswerMarks Guidance
PI correct answer2.5 M1
n=500
Obtains 500
AnswerMarks Guidance
CSO1.1b A1
Total4
QMarking instructions AO
Question 8:
--- 8(a) ---
8(a) | Obtains one correct value | 1.1b | B1 | ( )=27
P 3
( )=1000
P 10
Obtains both correct values | 1.1b | B1
--- 8(b) ---
8(b) | Forms cubic equation replacing
P ( n )=n3 (condone k3)
PI correct answer | 2.5 | M1 | n3 =1.25×108
n=500
Obtains 500
CSO | 1.1b | A1
Total | 4
Q | Marking instructions | AO | Mark | Typical solution
$$P(n) = \sum_{k=0}^{n} k^3 - \sum_{k=0}^{n-1} k^3 \text{ where } n \text{ is a positive integer.}$$

\begin{enumerate}[label=(\alph*)]
\item Find P(3) and P(10) [2 marks]

\item Solve the equation $P(n) = 1.25 \times 10^8$ [2 marks]
\end{enumerate}

\hfill \mbox{\textit{AQA Paper 1 2019 Q8 [4]}}