A flying drone is programmed to complete a series of movements in a horizontal plane relative to an origin O and a set of x-y-axes. In each case, the drone moves to a new position represented by the following transformations:
- a rotation anticlockwise of π/6 radians about O
- a reflection in the line y = x/√3
- a rotation clockwise of π/3 radians about O. All the movements are performed in the listed order.
Write down the matrix for each of the three transformations: (i) rotation anticlockwise of π/6 radians about O (ii) reflection in the line y = x/√3 (iii) rotation clockwise of π/3 radians about O
(i) rotation anticlockwise is (A1)
(ii) reflection in is (A1)
(iii) rotation clockwise is (A1)
Find a single matrix P that defines a transformation that represents the overall change in position by multiplying the three matrices in the correct order.
an attempt to multiply three matrices
(M1) A1A1
Find P².
(M1)A1 Note: Do not award if final answer not resolved into the identity matrix .
Hence state what the value of P² indicates for the possible movement of the drone.
Three drones are initially positioned at the points A, B and C. After performing the movements listed above, the drones are positioned at points A', B' and C' respectively.
Show that the area of triangle ABC is equal to the area of triangle A'B'C'.
Method 1:
- The determinant of matrix P is 1 (M1)
- This means the transformation preserves area (A1)
- Therefore triangle ABC has the same area as triangle A'B'C' (R1)
OR
Method 2:
- Area is preserved under rotations and reflections (M1)
- Each individual transformation preserves area (A1)
- Therefore the composite transformation preserves area (R1)
Find a single transformation that is equivalent to the three transformations represented by matrix P.