Geometry:Rotation about the origin Csec, gcse , Geometry EOC
When rotating a point 90 degrees counterclockwise about the origin our point A(x,y) becomes A'(-y,x). In other words, switch x and y and make y negative.
When rotating a point 180 degrees counterclockwise about the origin our point A(x,y) becomes A'(-x,-y). So all we do is make both x and y negative.
When rotating a point 90 clockwise about the origin our point A(x,y) becomes A'(y,-x). This means, we switch x and y and make x negative.
