Let the original coordinates be x 1 and y 1 and the rotation angle a be counterclockwise, then the new coordinates are

x2 = x 1*cos(a)？ - y 1*sin(a)

y2 = x 1 * sin(a)+y 1 * cos(a)

For example:

x 1 = 3； y 1 = 4；

a = 15 * pi/ 180；

y2？ =? x 1*sin(a)？ +? y 1*cos(a)

x2？ =? x 1*cos(a)？ -? y 1*sin(a)