Point A is at (-2 ,-4 ) and point B is at (-3 ,3 ). 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
Mar 20, 2018

Increase in distance due to the rotation of point A is

color(green)(vec(A'B) - vec(AB) = sqrt74 - sqrt50 = 1.53

Explanation:

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"Point " A (-2, -4), "Point " B (-3, 3)

Point A rotated about origin by (3pi)/2 clockwise.

To find change in distance between Ab due to rotation of point A.

A (-2, -4) -> A' (4,-2) , " shifted from III to IV quadrant"

Using distance formula,

vec(AB) = sqrt((-2+3)^2 + (-4-3)^2) = sqrt50

vec(A'B) = sqrt((4+3)^2 + (-2-3)^2) = sqrt74

Increase in distance due to the rotation of point A is

color(green)(vec(A'B) - vec(AB) = sqrt74 - sqrt50 = 1.53