Points A and B are at (4 ,9 ) and (7 ,5 ), respectively. Point A is rotated counterclockwise about the origin by (3pi)/2 and dilated about point C by a factor of 1/2 . If point A is now at point B, what are the coordinates of point C?

1 Answer
Jan 24, 2018

C=(5,14)

Explanation:

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

• " a point "(x,y)to(y,-x)

rArrA(4,9)toA'(9,-4)" where A' is the image of A"

rArrvec(CB)=color(red)(1/2)vec(CA')

rArrulb-ulc=1/2(ula'-ulc)=1/2ula'-1/2ulc

rArr-1/2ulc=1/2a'-ulb

color(white)(xxxxxx)=1/2((9),(-4))-((7),(5))=((-5/2),(-7))

rArrulc=-2((-5/2),(-7))=((5),(14))

rArrC=(5,14)