Points A and B are at (4 ,5 ) and (6 ,8 ), 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
Jul 29, 2018
Explanation:
"under a counterclockwise rotation about the origin of "(3pi)/2
• " a point "(x,y)to(y,-x)
A(4,5)toA'(5,-4)" where A' is the image of A"
vec(CB)=color(red)(4)vec(CA')
ulb-ulc=4(ula'-ulc)
ulb-ulc=4ula'-4ulc
3ulc=4ula'-ulb
color(white)(3ulc)=4((5),(-4))-((6),(8))
color(white)(3ulc)=((20),(-16))-((6),(8))=((14),(-24))
ulc=1/3((14),(-24))=((14/3),(-8))
rArrC=(14/3,-8)