Points A and B are at (7 ,3 ) and (5 ,9 ), respectively. Point A is rotated counterclockwise about the origin by (3pi)/2 and dilated about point C by a factor of 2 . If point A is now at point B, what are the coordinates of point C?

1 Answer
Jun 21, 2018

C=(1,-23)

Explanation:

"under a counterclockwise rotation about the origin of "(3pi)/2

• " a point "(x,y)to(y,-x)

A(7,3)toA'(3,-7)

vec(CB)=color(red)(2)vec(CA')

ulb-ulc=2(ula'-ulc)

ulb-ulc=2ula'-2ulc

ulc=2ula'-ulb

color(white)(ulc)=2((3),(-7))-((5),(9))

color(white)(ulc)=((6),(-14))-((5),(9))=((1),(-23))

rArrC=(1,-23)