Point A is at (4 ,-5 ) and point B is at (-6 ,-2 ). Point A is rotated (3pi)/2 clockwise about the origin. What are the new coordinates of point A and by how much has the distance between points A and B changed?

1 Answer
Feb 16, 2018

New coordinates A’ (-5,-4)

Change in distance 1.3849, reduction.

Explanation:

Given A (4, -5), B (-6,-2). Rotated about origin by (3pi)/2#

To find A’ and A’B - AB

vec(AB) = sqrt((4+6)^2 + (-5+2)^2) = sqrt109

Coordinates of A’ (-5,-4)

vec(A’B) = sqrt((-5-4)^2 + (-4+5)^2) = sqrt 82

Change in distance vec(AB) - vec(A’B) = sqrt109 - sqrt82 ~~ 1.3849