Matrices

• -1 0

  0 -1

  Rotation 180 degrees about the origin
• 0 1

  -1 0

  Rotation 90 degrees clockwise
• 0 -1

  1 0

  Rotation 90 degrees anticlockwise
• 1 0

  0 -1

  Reflection across x-axis
• -1 0

  0 1

  Reflection across y-axis
• 0 1

  1 0

  Reflection across y=x
• 0 -1

  -1 0

  Reflection across y=-x
• SF 0

  0 1

  Stretch in x-direction
• 1 0

  0 SF

  Stretch in y direction
• SF 0

  0 SF

  Enlargement by SF
• Rotation by 90 degrees defaults to 90 degrees anticlockwise unless stated otherwise