Combinations of transformations

Combinations of Transformations Revision Content

Basics of Mathematical Transformations

  • A transformation is the process that changes the position or direction of a shape.
  • Transformations in maths include translation, reflection, rotation, and enlargement.
  • A combination of transformations refers to when more than one transformation is performed on a point, line or shape.

Translations

  • A translation is a transformation that moves each point of a shape the same distance in the same direction.
  • It doesn’t change the shape or size, but only its position.
  • Translations are denoted as vectors, e.g., (5, -3) meaning move 5 units right and 3 units down.

Reflections

  • A reflection is a transformation representing a flip of a shape over a line, known as the line of reflection.
  • Reflection does not alter the size of a shape; it reverses the orientation.
  • The corresponding points in the original and reflected shape are equal distance from the line of reflection.

Rotations

  • A rotation is a transformation that turns a shape about a fixed point, known as the center of rotation.
  • The amount of rotation is usually specified in degree or radians, and the direction of rotation (clockwise or anticlockwise).
  • A rotation does not alter the size or shape, just its orientation and position.

Enlargements

  • An enlargement is a transformation that alters the size of a shape but not its shape.
  • It’s defined by its scale factor and its center of enlargement.
  • If the scale factor is larger than 1, the shape increases in size. If it’s smaller than 1, the shape reduces in size.

Combinations of Transformations

  • Combining transformations involves performing more than one transformation on a shape, one after the other.
  • The transformations can be the same type or different types. For example, you could perform two rotations, or a translation followed by a reflection.
  • The order of transformations does matter in certain circumstances. For example, a rotation followed by a translation can yield different results than a translation followed by a rotation.
  • With proper combination of transformations, every point in the plane can move to any other point.
  • It’s very common in mathematics curriculum to probe understanding of combinations of transformations.

Inverse Transformations

  • Every transformation has an inverse transformation, which reverses the effect of the original transformation.
  • For example, the inverse of a translation by vector (a, b) is a translation by vector (-a, -b).
  • Applying a transformation and then its inverse brings the shape back to its original position.