Points A and B are at (8 ,5 ) and (8 ,2 ), respectively. Point A is rotated counterclockwise about the origin by (3pi)/2 and dilated about point C by a factor of 3 . If point A is now at point B, what are the coordinates of point C?
1 Answer
May 28, 2018
Explanation:
"under a counterclockwise rotation about the origin of "(3pi)/2
• " a point "(x,y)to(y,-x)
A(8,5)toA'(5,-8)" where A' is the image of A"
vec(CB)=color(red)(3)vec(CA')
ulb-ulc=3(ula'-ulc)
ulb-ulc=3ula'-3ulc
2ulc=3ula'-ulb
color(white)(2ulc)=3((5),(-8))-((8),(2))
color(white)(2ulc)=((15),(-24))-((8),(2))=((7),(-26))
ulc=1/2((7),(-26))=((7/2),(-13))
rArrC=(7/2,-13)