13
8
1
\end{array} \right) + \lambda \left( \begin{array} { r }
2
2
- 1
\end{array} \right) \text {, where } \lambda \text { is a scalar parameter. }$$
The point \(A\) lies on \(l\) and has coordinates \(( 3 , - 2,6 )\).
The point \(P\) has position vector ( \(- \boldsymbol { i } + 2 \boldsymbol { k }\) ) relative to \(O\).
Given that vector \(\overrightarrow { P A }\) is perpendicular to \(l\), and that point \(B\) is a point on \(l\) such that \(\angle B P A = 45 ^ { \circ }\), find the coordinates of the two possible positions of \(B\).
(5)
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9. Prove by induction that for \(n \in \mathbb { Z } ^ { + }\)
$$\mathrm { f } ( n ) = 4 ^ { n + 1 } + 5 ^ { 2 n - 1 }$$
is divisible by 21
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10. The curve defined by the parametric equations
$$x = 2 \cos \theta , y = 3 \sin ( 2 \theta ) \text { and } \theta \in [ 0,2 \pi ]$$
is shown below.
The point \(P \left( \sqrt { 3 } , \frac { 3 \sqrt { 3 } } { 2 } \right)\) is marked on the curve.
\includegraphics[max width=\textwidth, alt={}, center]{a02ed733-d5ee-45a7-a39a-e40f3a36e659-22_604_826_518_758}
- Show that the equation of the normal to the curve at \(P\) can be written as \(3 y - x = \frac { 7 \sqrt { 3 } } { 2 }\)
- Show that the Cartesian equation of the curve may be written as \(a y ^ { 2 } + b x ^ { 4 } + c x ^ { 2 } = 0\) where \(a\), \(b\) and \(c\) are integers to be found.
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11. Solve the differential equation
$$2 \cot x \frac { \mathrm {~d} y } { \mathrm {~d} x } = \left( 4 - y ^ { 2 } \right)$$
for which \(y = 0\) at \(x = \frac { \pi } { 3 }\), giving your answer in the form \(\sec ^ { 2 } x = \mathrm { g } ( y )\).
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12.
A linear transformation T of the \(x - y\) plane has an associated matrix \(\mathbf { M }\), where \(\mathbf { M } = \left( \begin{array} { l c } \lambda & k
1 & \lambda - k \end{array} \right)\), and \(\lambda\)
and \(k\) are real constants. and \(k\) are real constants. - You are given that \(\operatorname { det } \mathbf { M } > 0\) for all values of \(\lambda\).
- Find the range of possible values of \(k\).
- What is the significance of the condition \(\operatorname { det } \mathbf { M } > 0\) for the transformation T ?
For the remainder of this question, take \(k = - 2\).
- Determine whether there are any lines through the origin that are invariant lines for the transformation T .
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13. (i) Show that \(\sin \left( 2 \theta + \frac { 1 } { 2 } \pi \right) = \cos 2 \theta\).
(ii) Hence solve the equation \(\sin 3 \theta = \cos 2 \theta\) for \(0 \leqslant \theta \leqslant 2 \pi\).
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