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
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)