Find reflection of point in line or plane

A question is this type if and only if it asks to find the image of a point after reflection in a line or plane.

7 questions · Challenging +1.2

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CAIE P3 2017 June Q9
11 marks Standard +0.3
9 Relative to the origin \(O\), the point \(A\) has position vector given by \(\overrightarrow { O A } = \mathbf { i } + 2 \mathbf { j } + 4 \mathbf { k }\). The line \(l\) has equation \(\mathbf { r } = 9 \mathbf { i } - \mathbf { j } + 8 \mathbf { k } + \mu ( 3 \mathbf { i } - \mathbf { j } + 2 \mathbf { k } )\).
  1. Find the position vector of the foot of the perpendicular from \(A\) to \(l\). Hence find the position vector of the reflection of \(A\) in \(l\).
  2. Find the equation of the plane through the origin which contains \(l\). Give your answer in the form \(a x + b y + c z = d\).
  3. Find the exact value of the perpendicular distance of \(A\) from this plane.
Edexcel P4 2021 October Q7
9 marks Standard +0.8
7. With respect to a fixed origin \(O\),
  • the line \(l\) has equation \(\mathbf { r } = \left( \begin{array} { r } 4 \\ 2 \\ - 3 \end{array} \right) + \lambda \left( \begin{array} { r } - 4 \\ - 3 \\ 5 \end{array} \right)\) where \(\lambda\) is a scalar constant
  • the point \(A\) has position vector \(9 \mathbf { i } - 3 \mathbf { j } + 2 \mathbf { k }\)
Given that \(X\) is the point on \(l\) nearest to \(A\),
  1. find
    1. the coordinates of \(X\)
    2. the shortest distance from \(A\) to \(l\). Give your answer in the form \(\sqrt { d }\), where \(d\) is an integer. The point \(B\) is the image of \(A\) after reflection in \(l\).
  2. Find the position vector of \(B\). Solutions relying on calculator technology are not acceptable. \begin{figure}[h]
    \includegraphics[alt={},max width=\textwidth]{08756c4b-6619-42da-ac8a-2bf065c01de8-26_668_661_408_644} \captionsetup{labelformat=empty} \caption{Figure 3}
    \end{figure}
Edexcel AEA 2011 June Q6
19 marks Challenging +1.8
6.The line \(L\) has equation $$\mathbf { r } = \left( \begin{array} { r } 13 \\ - 3 \\ - 8 \end{array} \right) + t \left( \begin{array} { r } - 5 \\ 3 \\ 4 \end{array} \right)$$ The point \(P\) has position vector \(\left( \begin{array} { r } - 7 \\ 2 \\ 7 \end{array} \right)\) .
The point \(P ^ { \prime }\) is the reflection of \(P\) in \(L\) .
(a)Find the position vector of \(P ^ { \prime }\) .
(b)Show that the point \(A\) with position vector \(\left( \begin{array} { r } - 7 \\ 9 \\ 8 \end{array} \right)\) lies on \(L\) .
(c)Show that angle \(P A P ^ { \prime } = 120 ^ { \circ }\) . \begin{figure}[h]
\includegraphics[alt={},max width=\textwidth]{12d3f92f-8464-4ba1-93a2-c7b841e3d3de-5_483_1367_1263_347} \captionsetup{labelformat=empty} \caption{Figure 3}
\end{figure} The point \(B\) lies on \(L\) and \(A P B P ^ { \prime }\) forms a kite as shown in Figure 3.
The area of the kite is \(50 \sqrt { } 3\) (d)Find the position vector of the point \(B\) .
(e)Show that angle \(B P A = 90 ^ { \circ }\) . The circle \(C\) passes through the points \(A , P , P ^ { \prime }\) and \(B\) .
(f)Find the position vector of the centre of \(C\) .
Edexcel AEA 2011 June Q13
Challenging +1.8
13
- 3
- 8 \end{array} \right) + t \left( \begin{array} { r } - 5
3
4 \end{array} \right)$$ The point \(P\) has position vector \(\left( \begin{array} { r } - 7 \\ 2 \\ 7 \end{array} \right)\) .\\ The point \(P ^ { \prime }\) is the reflection of \(P\) in \(L\) .\\ (a)Find the position vector of \(P ^ { \prime }\) .\\ (b)Show that the point \(A\) with position vector \(\left( \begin{array} { r } - 7 \\ 9 \\ 8 \end{array} \right)\) lies on \(L\) .\\ (c)Show that angle \(P A P ^ { \prime } = 120 ^ { \circ }\) . \begin{figure}[h]
\includegraphics[alt={},max width=\textwidth]{12d3f92f-8464-4ba1-93a2-c7b841e3d3de-5_483_1367_1263_347} \captionsetup{labelformat=empty} \caption{Figure 3}
\end{figure} The point \(B\) lies on \(L\) and \(A P B P ^ { \prime }\) forms a kite as shown in Figure 3.\\ The area of the kite is \(50 \sqrt { } 3\)\\ (d)Find the position vector of the point \(B\) .\\ (e)Show that angle \(B P A = 90 ^ { \circ }\) . The circle \(C\) passes through the points \(A , P , P ^ { \prime }\) and \(B\) .\\ (f)Find the position vector of the centre of \(C\) .\\ 7.\\ \includegraphics[max width=\textwidth, alt={}, center]{12d3f92f-8464-4ba1-93a2-c7b841e3d3de-6_675_1145_237_459} \section*{Figure 4} (a)Figure 4 shows a sketch of the curve with equation \(y = \mathrm { f } ( x )\) ,where $$\mathrm { f } ( x ) = \frac { x ^ { 2 } - 5 } { 3 - x } , \quad x \in \mathbb { R } , x \neq 3$$ The curve has a minimum at the point \(A\) ,with \(x\)-coordinate \(\alpha\) ,and a maximum at the point \(B\) , with \(x\)-coordinate \(\beta\) . Find the value of \(\alpha\) ,the value of \(\beta\) and the \(y\)-coordinates of the points \(A\) and \(B\) .\\ (b) The functions g and h are defined as follows $$\begin{array} { l l } \mathrm { g } : x \rightarrow x + p & x \in \mathbb { R }
\mathrm {~h} : x \rightarrow | x | & x \in \mathbb { R } \end{array}$$ where \(p\) is a constant. \begin{figure}[h]
\includegraphics[alt={},max width=\textwidth]{12d3f92f-8464-4ba1-93a2-c7b841e3d3de-7_673_1338_591_367} \captionsetup{labelformat=empty} \caption{Figure 5}
\end{figure} Figure 5 shows a sketch of the curve with equation \(y = \mathrm { h } ( \mathrm { fg } ( x ) + q ) , x \in \mathbb { R } , x \neq 0\), where \(q\) is a constant. The curve is symmetric about the \(y\)-axis and has minimum points at \(C\) and \(D\).
  1. Find the value of \(p\) and the value of \(q\).
  2. Write down the coordinates of \(D\).\\ (c) The function \(m\) is given by $$\mathrm { m } ( x ) = \frac { x ^ { 2 } - 5 } { 3 - x } , \quad x \in \mathbb { R } , x \leqslant \alpha$$ where \(\alpha\) is the \(x\)-coordinate of \(A\) as found in part (a).
  3. Find \(\mathrm { m } ^ { - 1 }\)
  4. Write down the domain of \(\mathrm { m } ^ { - 1 }\)
  5. Find the value of \(t\) such that \(\mathrm { m } ( t ) = \mathrm { m } ^ { - 1 } ( t )\)
OCR Further Pure Core 1 2019 June Q8
6 marks Standard +0.8
8 The equation of a plane is \(4 x + 2 y + z = 7\).
The point \(A\) has coordinates \(( 9,6,1 )\) and the point \(B\) is the reflection of \(A\) in the plane.
Find the coordinates of the point \(B\).
Edexcel CP1 Specimen Q8
7 marks Challenging +1.8
  1. The line \(l _ { 1 }\) has equation \(\frac { x - 2 } { 4 } = \frac { y - 4 } { - 2 } = \frac { z + 6 } { 1 }\)
The plane \(\Pi\) has equation \(x - 2 y + z = 6\) The line \(l _ { 2 }\) is the reflection of the line \(l _ { 1 }\) in the plane \(\Pi\).
Find a vector equation of the line \(l _ { 2 }\)
Edexcel FP3 Q9
18 marks Challenging +1.2
  1. The plane \(\Pi\) passes through the points
$$A ( - 1 , - 1,1 ) , B ( 4,2,1 ) \text { and } C ( 2,1,0 )$$
  1. Find a vector equation of the line perpendicular to \(\Pi\) which passes through the point \(D ( 1,2,3 )\).
  2. Find the volume of the tetrahedron \(A B C D\).
  3. Obtain the equation of \(\Pi\) in the form r.n \(= p\). The perpendicular from \(D\) to the plane \(\Pi\) meets \(\Pi\) at the point \(E\).
  4. Find the coordinates of \(E\).
  5. Show that \(D E = \frac { 11 \sqrt { 35 } } { 35 }\). The point \(D ^ { \prime }\) is the reflection of \(D\) in \(\Pi\).
  6. Find the coordinates of \(D ^ { \prime }\).
    (3)
    [0pt] [P6 June 2002 Qn 7]