Points A and B are at (8 ,5 )(8,5) and (2 ,2 )(2,2), respectively. Point A is rotated counterclockwise about the origin by (3pi)/2 3π2 and dilated about point C by a factor of 3 3. If point A is now at point B, what are the coordinates of point C?

1 Answer
Feb 27, 2018

C=(13/2,-13)C=(132,13)

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(8,5)toA'(5,-8)" where A' is the image of A"

rArrvec(CB)=color(red)(3)vec(CA')

rArrulb-ulc=3(ula'-ulc)

rArrulb-ulc=3ula'-3ulc

rArr2ulc=3ula'-ulb

color(white)(rArr2ulc)=3((5),(-8))-((2),(2))

color(white)(rArr2ulc)=((15),(-24))-((2),(2))=((13),(-26))

rArrulc=1/2((-13),(-26))=((13/2),(-13))

rArrC=(13/2,-13)