Points A and B are at (8 ,3 ) and (5 ,4 ), respectively. Point A is rotated counterclockwise about the origin by pi/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 8, 2018
Explanation:
"under a counterclockwise rotation about the origin of "pi/2
• " a point "(x,y)to(-y,x)
A(8,3)toA'(-3,8)" 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((-3),(8))-((5),(4))
color(white)(ulc)=((-6),(16))-((5),(4))=((-11),(12))
rArrC=(-11,12)