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.