Verify invariant line property

A question is this type if and only if it asks to show or verify that a given line (e.g., y = kx) is invariant under a transformation, or to find k such that a line is invariant.

6 questions · Standard +0.4

4.03g Invariant points and lines
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OCR MEI Further Pure Core 2021 November Q6
4 marks Standard +0.3
6 Given that \(y = m x\) is an invariant line of the transformation with matrix \(\left( \begin{array} { r r } 1 & 2 \\ 2 & - 2 \end{array} \right)\), determine the possible values of \(m\). Section B (113 marks)
Answer all the questions.
AQA Further Paper 2 2024 June Q10
4 marks Standard +0.8
The matrix \(\mathbf{C}\) is defined by $$\mathbf{C} = \begin{bmatrix} 3 & 2 \\ -4 & 5 \end{bmatrix}$$ Prove that the transformation represented by \(\mathbf{C}\) has no invariant lines of the form \(y = kx\) [4 marks]
OCR Further Pure Core 1 2021 November Q9
5 marks Standard +0.3
You are given that the matrix \(\begin{pmatrix} 2 & 1 \\ -1 & 0 \end{pmatrix}\) represents a transformation T.
  1. You are given that the line with equation \(y = kx\) is invariant under T. Determine the value of \(k\). [4]
  2. Determine whether the line with equation \(y = kx\) in part (a) is a line of invariant points under T. [1]
OCR MEI Further Pure Core Specimen Q3
6 marks Standard +0.3
Transformation M is represented by matrix \(\mathbf{M} = \begin{pmatrix} 2 & 3 \\ 1 & 4 \end{pmatrix}\).
  1. On the diagram in the Printed Answer Booklet draw the image of the unit square under M. [2]
    1. Show that there is a constant \(k\) such that \(\mathbf{M} \begin{pmatrix} x \\ kx \end{pmatrix} = 5 \begin{pmatrix} x \\ kx \end{pmatrix}\) for all \(x\). [2]
    2. Hence find the equation of an invariant line under M. [1]
    3. Draw the invariant line from part (ii) (B) on your diagram for part (i). [1]
SPS SPS FM 2023 February Q4
5 marks Standard +0.3
  1. You are given that the matrix \(\begin{pmatrix} 2 & 1 \\ -1 & 0 \end{pmatrix}\) represents a transformation T. You are given that the line with equation \(y = kx\) is invariant under T. Determine the value of k. [4]
  2. Determine whether the line with equation \(y = kx\) in part above is a line of invariant points under T. [1]
SPS SPS FM Pure 2025 January Q3
8 marks Standard +0.3
$$\mathbf{A} = \begin{pmatrix} k & -2 \\ 1-k & k \end{pmatrix},$$ where \(k\) is constant. A transformation \(T : \mathbb{R}^2 \to \mathbb{R}^2\) is represented by the matrix \(\mathbf{A}\).
  1. Find the value of \(k\) for which the line \(y = 2x\) is mapped onto itself under \(T\). [3]
  2. Show that \(\mathbf{A}\) is non-singular for all values of \(k\). [3]
  3. Find \(\mathbf{A}^{-1}\) in terms of \(k\). [2]