The point P has coordinates (rcosf, rsin f) where the distance of P from the origin is OP=r and the line OP is at angle f to the x axis. Find the image of this point under the transformation given by the matrix
T1 = æ
ç
è
cos q
-sinq
sin q
cos q
ö
÷
ø
Draw a diagram and describe the effect of this transformation on the points of the plane.

The point P has coordinates (p,q) and the point P¢ is the reflection of P in the line y = xtanq. In the diagram below the lines P¢X¢ and XA¢ are perpendicular to the line OA¢X¢. "

Reflection

Prove that OX = OX¢ = p, P¢X¢ = PX = q and OA = OA¢ = pcos2q. Find the lengths BP¢AX¢ and BX¢ and hence prove that transformation given by the matrix
T2 = æ
ç
è
cos 2q
sin2q
sin2q
-cos2q
ö
÷
ø
gives a reflection in the line y=tanq.