Investigate, generalise and apply the effect on the co-ordinates of: (a) the point (x ; y) after rotation around the origin through an angle of 90º or 180º; (b) the vertices
(x1 ; y1), (x2 ; y2),... (xn ; yn)
of a polygon after enlargement through the origin, by a constant factor k.
(a) Use the compound angle identities to generalise the effect on the co-ordinates of a point (x ; y) after rotation about the origin through an angle θ. (b) Demonstrate the knowledge · that rigid transformations (translations, reflections, rotations and glide reflections) preserve shape and size, · and that enlargement preserves shape but not size.
Transformations & Enlargements
- Determine the rule of transformations that has occurred.
- Determine the factor of a dilation (enlargement or reduction).
- The factor of dilation is an element of the rational numbers.
- Use a transformation rule to sketch images of transformations of shapes, determine points of the image of a transformation of a shape and determine the relationship of the area of the image in relation to its original shape.
Rotations that are generated in
- an anticlockwise direction are regarded as positive whilst
- clockwise rotations are regarded as negative.