Points A and B are at (7 ,3 ) and (5 ,9 ), 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
Jun 21, 2018
Explanation:
"under a counterclockwise rotation about the origin of "(3pi)/2
• " a point "(x,y)to(y,-x)
A(7,3)toA'(3,-7)
vec(CB)=color(red)(2)vec(CA')
ulb-ulc=2(ula'-ulc)
ulb-ulc=2ula'-2ulc
ulc=2ula'-ulb
color(white)(ulc)=2((3),(-7))-((5),(9))
color(white)(ulc)=((6),(-14))-((5),(9))=((1),(-23))
rArrC=(1,-23)