I don't even know what a system is, but when you want to rotate the points of any x and y equation around the origin, you replace each instance of x with (x*cos(t) + y*sin(t)) and replace each instance of y with (y*cos(t) - x*sin(t)) where t is the angle of how much you want to rotate the points counterclockwise.
Answers & Comments
Verified answer
I don't even know what a system is, but when you want to rotate the points of any x and y equation around the origin, you replace each instance of x with (x*cos(t) + y*sin(t)) and replace each instance of y with (y*cos(t) - x*sin(t)) where t is the angle of how much you want to rotate the points counterclockwise.