Edexcel C4 (Core Mathematics 4) 2014 June

Question 1
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  1. A curve \(C\) has the equation
$$x ^ { 3 } + 2 x y - x - y ^ { 3 } - 20 = 0$$
  1. Find \(\frac { \mathrm { d } y } { \mathrm {~d} x }\) in terms of \(x\) and \(y\).
  2. Find an equation of the tangent to \(C\) at the point \(( 3 , - 2 )\), giving your answer in the form \(a x + b y + c = 0\), where \(a , b\) and \(c\) are integers.
Question 3
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Question 4
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Question 6
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  1. A curve \(C\) has the equation
$$x ^ { 3 } + 2 x y - x - y ^ { 3 } - 20 = 0$$
  1. Find \(\frac { \mathrm { d } y } { \mathrm {~d} x }\) in terms of \(x\) and \(y\).
  2. Find an equation of the tangent to \(C\) at the point \(( 3 , - 2 )\), giving your answer in the form \(a x + b y + c = 0\), where \(a , b\) and \(c\) are integers.
    2. Given that the binomial expansion of \(( 1 + k x ) ^ { - 4 } , | k x | < 1\), is $$1 - 6 x + A x ^ { 2 } + \ldots$$
  3. find the value of the constant \(k\),
  4. find the value of the constant \(A\), giving your answer in its simplest form.
    3. \begin{figure}[h]
    \includegraphics[alt={},max width=\textwidth]{a9963b13-7db4-4a1d-8c75-829f4aade994-05_659_865_269_550} \captionsetup{labelformat=empty} \caption{Figure 1}
    \end{figure} Figure 1 shows a sketch of part of the curve with equation \(y = \frac { 10 } { 2 x + 5 \sqrt { } x } , x > 0\)
    The finite region \(R\), shown shaded in Figure 1, is bounded by the curve, the \(x\)-axis, and the lines with equations \(x = 1\) and \(x = 4\) The table below shows corresponding values of \(x\) and \(y\) for \(y = \frac { 10 } { 2 x + 5 \sqrt { } x }\)
    \(x\)1234
    \(y\)1.428570.903260.55556
  5. Complete the table above by giving the missing value of \(y\) to 5 decimal places.
  6. Use the trapezium rule, with all the values of \(y\) in the completed table, to find an estimate for the area of \(R\), giving your answer to 4 decimal places.
  7. By reference to the curve in Figure 1, state, giving a reason, whether your estimate in part (b) is an overestimate or an underestimate for the area of \(R\).
  8. Use the substitution \(u = \sqrt { } x\), or otherwise, to find the exact value of $$\int _ { 1 } ^ { 4 } \frac { 10 } { 2 x + 5 \sqrt { x } } d x$$ 4. \begin{figure}[h]
    \includegraphics[alt={},max width=\textwidth]{a9963b13-7db4-4a1d-8c75-829f4aade994-07_618_703_246_625} \captionsetup{labelformat=empty} \caption{Figure 2}
    \end{figure} A vase with a circular cross-section is shown in Figure 2. Water is flowing into the vase. When the depth of the water is \(h \mathrm {~cm}\), the volume of water \(V \mathrm {~cm} ^ { 3 }\) is given by $$V = 4 \pi h ( h + 4 ) , \quad 0 \leqslant h \leqslant 25$$ Water flows into the vase at a constant rate of \(80 \pi \mathrm {~cm} ^ { 3 } \mathrm {~s} ^ { - 1 }\) Find the rate of change of the depth of the water, in \(\mathrm { cms } ^ { - 1 }\), when \(h = 6\)
    5. \begin{figure}[h]
    \includegraphics[alt={},max width=\textwidth]{a9963b13-7db4-4a1d-8c75-829f4aade994-08_675_1262_267_340} \captionsetup{labelformat=empty} \caption{Figure 3}
    \end{figure} Figure 3 shows a sketch of the curve \(C\) with parametric equations $$x = 4 \cos \left( t + \frac { \pi } { 6 } \right) , \quad y = 2 \sin t , \quad 0 \leqslant t < 2 \pi$$
  9. Show that $$x + y = 2 \sqrt { 3 } \cos t$$
  10. Show that a cartesian equation of \(C\) is $$( x + y ) ^ { 2 } + a y ^ { 2 } = b$$ where \(a\) and \(b\) are integers to be determined.
    \includegraphics[max width=\textwidth, alt={}, center]{a9963b13-7db4-4a1d-8c75-829f4aade994-09_104_51_2617_1900}
    6. (i) Find $$\int x \mathrm { e } ^ { 4 x } \mathrm {~d} x$$ (ii) Find $$\int \frac { 8 } { ( 2 x - 1 ) ^ { 3 } } \mathrm {~d} x , \quad x > \frac { 1 } { 2 }$$ (iii) Given that \(y = \frac { \pi } { 6 }\) at \(x = 0\), solve the differential equation $$\frac { \mathrm { d } y } { \mathrm {~d} x } = \mathrm { e } ^ { x } \operatorname { cosec } 2 y \operatorname { cosec } y$$
Question 7
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7. \begin{figure}[h]
\includegraphics[alt={},max width=\textwidth]{a9963b13-7db4-4a1d-8c75-829f4aade994-12_681_1203_258_376} \captionsetup{labelformat=empty} \caption{Figure 4}
\end{figure} Figure 4 shows a sketch of part of the curve \(C\) with parametric equations $$x = 3 \tan \theta , \quad y = 4 \cos ^ { 2 } \theta , \quad 0 \leqslant \theta < \frac { \pi } { 2 }$$ The point \(P\) lies on \(C\) and has coordinates ( 3,2 ). The line \(l\) is the normal to \(C\) at \(P\). The normal cuts the \(x\)-axis at the point \(Q\).
  1. Find the \(x\) coordinate of the point \(Q\). The finite region \(S\), shown shaded in Figure 4, is bounded by the curve \(C\), the \(x\)-axis, the \(y\)-axis and the line \(l\). This shaded region is rotated \(2 \pi\) radians about the \(x\)-axis to form a solid of revolution.
  2. Find the exact value of the volume of the solid of revolution, giving your answer in the form \(p \pi + q \pi ^ { 2 }\), where \(p\) and \(q\) are rational numbers to be determined.
    [0pt] [You may use the formula \(V = \frac { 1 } { 3 } \pi r ^ { 2 } h\) for the volume of a cone.]
Question 8
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8. Relative to a fixed origin \(O\), the point \(A\) has position vector \(\left( \begin{array} { r } - 2
4
7 \end{array} \right)\) and the point \(B\) has position vector \(\left( \begin{array} { r } - 1
3
8 \end{array} \right)\) The line \(l _ { 1 }\) passes through the points \(A\) and \(B\).
  1. Find the vector \(\overrightarrow { A B }\).
  2. Hence find a vector equation for the line \(l _ { 1 }\) The point \(P\) has position vector \(\left( \begin{array} { l } 0
    2
    3 \end{array} \right)\)
    Given that angle \(P B A\) is \(\theta\),
  3. show that \(\cos \theta = \frac { 1 } { 3 }\) The line \(l _ { 2 }\) passes through the point \(P\) and is parallel to the line \(l _ { 1 }\)
  4. Find a vector equation for the line \(l _ { 2 }\) The points \(C\) and \(D\) both lie on the line \(l _ { 2 }\)
    Given that \(A B = P C = D P\) and the \(x\) coordinate of \(C\) is positive,
  5. find the coordinates of \(C\) and the coordinates of \(D\).
  6. find the exact area of the trapezium \(A B C D\), giving your answer as a simplified surd.