Question

Write a function to represent x,y the point rotated 90 counterclockwise about the origin.

R(x,y)=

Answer 1

R(x.y) (x, y ) → (- y, x )

simply as when quadrant 1 is shown (top right grid) x,y is positive.

Counterclockwise from quadrant 2 = negative y (top left grid is counterclockwise)

If quadrant 1 is shown first and it said counterclockwise 180 then it would be diagonally across the grid and show quadrant 3 = negative x, negative y

Explanation: