# Point A is at #(1 ,3 )# and point B is at #(-7 ,-5 )#. Point A is rotated #pi/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

May 16, 2018

#### Explanation:

We can produce a rotation about the origin by using the transformation matrix:

This is for anticlockwise rotation, so for clockwise rotation we use the angle:

So we have:

Distance between A and B:

Distance between A' and B:

Change in distance: