Step 1: State the general rotation matrix for an anticlockwise rotation.
The matrix for an anticlockwise rotation of a point (x,y) about the origin through an angle θ is given by:
R(θ)=(cosθsinθ−sinθcosθ)
The transformed coordinates (x′,y′) are found by:
(x′y′)=(cosθsinθ−sinθcosθ)(xy)
This matrix is shown at the bottom of the provided image.
Step 2: Verify the rotation for 270∘ anticlockwise.
To verify the specific case of a 270∘ anticlockwise rotation shown in the image, we substitute θ=270∘ into the general rotation matrix:
R(270∘)=(cos(270∘)sin(270∘)−sin(270∘)cos(270∘))
We know that cos(270∘)=0 and sin(270∘)=−1.
Substitute these values:
R(270∘)=(0−1−(−1)0)=(0−110)
This matches the rotation matrix shown in the image for the 270∘ rotation.
Now, apply this matrix to a point (xy):
(x′y′)=(0−110)(xy)=((0)(x)+(1)(y)(−1)(x)+(0)(y))=(y−x)
This result (y−x) also matches the transformed coordinates shown in the image for a 270∘ anticlockwise rotation of (xy).
The general rotation matrix for an anticlockwise rotation through an angle θ is (cosθsinθ−sinθcosθ).
The specific rotation matrix for an anticlockwise rotation through 270∘ is (0−110).