Matrix Transformations Practice Questions

Question 1

3 marks

Write down the 2×22 \times 2 matrix that represents each of these transformations.

(a)

A reflection in the line y=0y = 0.

(b)

A rotation of 180∘180^\circ about the origin.

(c)

An enlargement, centre the origin, with scale factor 44.

Question 2

2 marks
(a)

Circle the transformation matrix that represents a rotation of 90∘90^\circ clockwise about the origin.

  • (01−10)\begin{pmatrix} 0 & 1 \\ -1 & 0 \end{pmatrix}
  • (0−110)\begin{pmatrix} 0 & -1 \\ 1 & 0 \end{pmatrix}
  • (−1001)\begin{pmatrix} -1 & 0 \\ 0 & 1 \end{pmatrix}
  • (0110)\begin{pmatrix} 0 & 1 \\ 1 & 0 \end{pmatrix}
(b)

Describe geometrically the single transformation represented by (−1001)\begin{pmatrix} -1 & 0 \\ 0 & 1 \end{pmatrix}

Question 3

2 marks

The transformation matrix T=(30−12)T = \begin{pmatrix} 3 & 0 \\ -1 & 2 \end{pmatrix}

Work out the image of the point (−2, 4)(-2,\ 4) under the transformation represented by TT.