Points A and B are at (4 ,3 ) and (5 ,2 ), 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
Feb 28, 2018

C=(1,-10)

Explanation:

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

• " a point "(x,y)to(y,-x)

rArrA(4,3)toA'(3,-4)" where A' is the image of A"

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

rArrulb-ulc=2(ula'-ulc)

rArrulb-ulc=2ula'-2ulc

rArrulc=2ula'-ulb

color(white)(rArrulc)=2((3),(-4))-((5),(2))

color(white)(rArrulc)=((6),(-8))-((5),(2))=((1),(-10))

rArrC=(1,-10)