Points A and B are at (7 ,3 )(7,3) and (3 ,2 )(3,2), respectively. Point A is rotated counterclockwise about the origin by (3pi)/2 3π2 and dilated about point C by a factor of 2 2. If point A is now at point B, what are the coordinates of point C?

1 Answer
May 18, 2018

C=(3,-16)C=(3,16)

Explanation:

"under a counterclockwise rotation about the origin of "(3pi)/2under a counterclockwise rotation about the origin of 3π2

• " a point "(x,y)to(y,-x) a point (x,y)(y,x)

rArrA(7,3)toA'(3,-7)" 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),(-7))-((3),(2))

color(white)(rArrulc)=((6),(-14))-((3),(2))=((3),(-16))

rArrC=(3,-16)