Edexcel P3 2020 October — Question 9 14 marks

Exam BoardEdexcel
ModuleP3 (Pure Mathematics 3)
Year2020
SessionOctober
Marks14
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicPartial Fractions
TypeTangent or normal to curve
DifficultyStandard +0.3 This is a straightforward multi-part question combining routine algebraic long division/partial fractions (part a), standard differentiation and tangent line equation (part b), and integration using the simplified form (part c). All techniques are standard P3/C3 material with no novel insights required, making it slightly easier than average.
Spec1.02y Partial fractions: decompose rational functions1.07m Tangents and normals: gradient and equations1.08d Evaluate definite integrals: between limits1.08j Integration using partial fractions

9. (a) Given that $$\frac { x ^ { 4 } - x ^ { 3 } - 10 x ^ { 2 } + 3 x - 9 } { x ^ { 2 } - x - 12 } \equiv x ^ { 2 } + P + \frac { Q } { x - 4 } \quad x > - 3$$ find the value of the constant \(P\) and show that \(Q = 5\) The curve \(C\) has equation \(y = \mathrm { g } ( x )\), where $$g ( x ) = \frac { x ^ { 4 } - x ^ { 3 } - 10 x ^ { 2 } + 3 x - 9 } { x ^ { 2 } - x - 12 } \quad - 3 < x < 3.5 \quad x \in \mathbb { R }$$ (b) Find the equation of the tangent to \(C\) at the point where \(x = 2\) Give your answer in the form \(y = m x + c\), where \(m\) and \(c\) are constants to be found. \begin{figure}[h]
\includegraphics[alt={},max width=\textwidth]{96948fd3-5438-4e95-b41b-2f649ca8dfac-28_876_961_1055_495} \captionsetup{labelformat=empty} \caption{Figure 4}
\end{figure} Figure 4 shows a sketch of the curve \(C\).
The region \(R\), shown shaded in Figure 4, is bounded by \(C\), the \(y\)-axis, the \(x\)-axis and the line with equation \(x = 2\) (c) Find the exact area of \(R\), writing your answer in the form \(a + b \ln 2\), where \(a\) and \(b\) are constants to be found. \includegraphics[max width=\textwidth, alt={}, center]{96948fd3-5438-4e95-b41b-2f649ca8dfac-31_2255_50_314_34}
VIHV SIHII NI I IIIM I ON OCVIAV SIHI NI JYHAM ION OOVI4V SIHI NI JLIYM ION OO
\includegraphics[max width=\textwidth, alt={}, center]{96948fd3-5438-4e95-b41b-2f649ca8dfac-32_106_113_2524_1832}

9. (a) Given that

$$\frac { x ^ { 4 } - x ^ { 3 } - 10 x ^ { 2 } + 3 x - 9 } { x ^ { 2 } - x - 12 } \equiv x ^ { 2 } + P + \frac { Q } { x - 4 } \quad x > - 3$$

find the value of the constant $P$ and show that $Q = 5$

The curve $C$ has equation $y = \mathrm { g } ( x )$, where

$$g ( x ) = \frac { x ^ { 4 } - x ^ { 3 } - 10 x ^ { 2 } + 3 x - 9 } { x ^ { 2 } - x - 12 } \quad - 3 < x < 3.5 \quad x \in \mathbb { R }$$

(b) Find the equation of the tangent to $C$ at the point where $x = 2$

Give your answer in the form $y = m x + c$, where $m$ and $c$ are constants to be found.

\begin{figure}[h]
\begin{center}
  \includegraphics[alt={},max width=\textwidth]{96948fd3-5438-4e95-b41b-2f649ca8dfac-28_876_961_1055_495}
\captionsetup{labelformat=empty}
\caption{Figure 4}
\end{center}
\end{figure}

Figure 4 shows a sketch of the curve $C$.\\
The region $R$, shown shaded in Figure 4, is bounded by $C$, the $y$-axis, the $x$-axis and the line with equation $x = 2$\\
(c) Find the exact area of $R$, writing your answer in the form $a + b \ln 2$, where $a$ and $b$ are constants to be found.

\includegraphics[max width=\textwidth, alt={}, center]{96948fd3-5438-4e95-b41b-2f649ca8dfac-31_2255_50_314_34}\\

\begin{center}
\begin{tabular}{|l|l|l|}
\hline
VIHV SIHII NI I IIIM I ON OC & VIAV SIHI NI JYHAM ION OO & VI4V SIHI NI JLIYM ION OO \\
\hline
\end{tabular}
\end{center}

\includegraphics[max width=\textwidth, alt={}, center]{96948fd3-5438-4e95-b41b-2f649ca8dfac-32_106_113_2524_1832}

\hfill \mbox{\textit{Edexcel P3 2020 Q9 [14]}}