Points A and B are at (2 ,1 ) and (3 ,5 ), 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
Aug 4, 2018

C=(-1,-9)

Explanation:

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

• " a point "(x,y)to(y,-x)

A(2,1)toA'(1,-2)" where A' is the image of A"

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

ulb-ulc=2(ula'-ulc)

ulb-ulc=2ula'-2ulc

ulc=2ula'-ulb

color(white)(ulc)=2((1),(-2))-((3),(5))

color(white)(ulc)=((2),(-4))-((3),(5))=((-1),(-9))

rArrC=(-1,-9)