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

C=(-11,-1)C=(11,1)

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(2,4)toA'(-4,2)" 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((-4),(2))-((3),(5))

color(white)(rArrulc)=((-8),(4))-((3),(5))=((-11),(-1))

rArrC=(-11,-1)