Points A and B are at (1 ,5 ) and (2 ,3 ), respectively. Point A is rotated counterclockwise about the origin by (3pi)/2 and dilated about point C by a factor of 4 . If point A is now at point B, what are the coordinates of point C?
1 Answer
Mar 14, 2018
Explanation:
"under a counterclockwise rotation about the origin of "(3pi)/2
• " a point "(x,y)to(y,x)
rArrA(1,5)toA'(5,1)" where A' is the image of A"
rArrvec(CB)=color(red)(4)vec(CA')
rArrulb-ulc=4(ula'-ulc)
rArrulb-ulc=4ula'-4ulc
rArr3ulc=4ula'-ulb
color(white)(rArr3ulc)=4((5),(1))-((2),(3))
color(white)(rArr3ulc)=((20),(4))-((2),(3))=((18),(1))
rArrulc=1/3((18),(1))=((6),(1/3))
rArrC=(6,1/3)