Question

What is the image point of (2, -1) after the transformation R90 ?

Answer 1

A rotation by 90 degrees counterclockwise is given by the rule:

`(x,y)\rightarrow(-y,x)`

For the point (2,-1) we have:

`(2,-1)\rightarrow(-(-1),2)=(1,2)`

Therefore, the image of the point (2,-1) after a reflection of 90 degrees counterclockwise is:

`(1,2)`