AQA FP1 2005 January — Question 7

Exam BoardAQA
ModuleFP1 (Further Pure Mathematics 1)
Year2005
SessionJanuary
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicCurve Sketching
TypeLogarithmic graph for power law
DifficultyModerate -0.3 This is a standard data linearization exercise requiring students to transform given data points, plot them, and extract constants from gradient and intercept. While it involves cube and square transformations, the method is routine for FP1 students and requires only careful arithmetic and graph reading rather than problem-solving insight.
Spec1.06h Logarithmic graphs: reduce y=ax^n and y=kb^x to linear form

7 [Figure 1, printed on the insert, is provided for use in this question.]
The variables \(x\) and \(y\) are known to be related by an equation of the form $$y ^ { 3 } = a x ^ { 2 } + b$$ where \(a\) and \(b\) are constants. Experimental evidence has provided the following approximate values:
\(x\)1.54.05.06.58.0
\(y\)5.06.37.08.09.0
  1. On Figure 1, draw a linear graph connecting the variables \(X\) and \(Y\), where $$X = x ^ { 2 } \quad \text { and } \quad Y = y ^ { 3 }$$
  2. From your graph, find approximate values for the constants \(a\) and \(b\).

Question 7:
Part (a)
AnswerMarks Guidance
\((X, Y)\) values: \((2.25, 125)\), \((16, 250)\), \((25, 343)\), \((42.25, 512)\), \((64, 729)\)B2,1 PI by candidate's graph; ft wrong values
Five points accurately plottedB2,1ft
Reasonable straight line drawnB1ft (5 marks) ft errors in plotting
Part (b)
AnswerMarks
Calculation of gradient of lineM1
Value of \(a\) equal to gradient foundA1
Value of \(b\) = \(y\)-intercept of lineB1 (3 marks)
## Question 7:

**Part (a)**
$(X, Y)$ values: $(2.25, 125)$, $(16, 250)$, $(25, 343)$, $(42.25, 512)$, $(64, 729)$ | B2,1 | PI by candidate's graph; ft wrong values
Five points accurately plotted | B2,1ft |
Reasonable straight line drawn | B1ft (5 marks) | ft errors in plotting

**Part (b)**
Calculation of gradient of line | M1 |
Value of $a$ equal to gradient found | A1 |
Value of $b$ = $y$-intercept of line | B1 (3 marks) |

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7 [Figure 1, printed on the insert, is provided for use in this question.]\\
The variables $x$ and $y$ are known to be related by an equation of the form

$$y ^ { 3 } = a x ^ { 2 } + b$$

where $a$ and $b$ are constants.

Experimental evidence has provided the following approximate values:

\begin{center}
\begin{tabular}{ | l | l | l | l | l | l | }
\hline
$x$ & 1.5 & 4.0 & 5.0 & 6.5 & 8.0 \\
\hline
$y$ & 5.0 & 6.3 & 7.0 & 8.0 & 9.0 \\
\hline
\end{tabular}
\end{center}
\begin{enumerate}[label=(\alph*)]
\item On Figure 1, draw a linear graph connecting the variables $X$ and $Y$, where

$$X = x ^ { 2 } \quad \text { and } \quad Y = y ^ { 3 }$$
\item From your graph, find approximate values for the constants $a$ and $b$.
\end{enumerate}

\hfill \mbox{\textit{AQA FP1 2005 Q7}}