圆的方程为:(x-a)²+(y-b)²=r²
圆均匀的分为n份,那么每份的角度为360°/n,则第i(i≤n)个点横、纵坐标分别为:
x1=a+r,y1=b;
x2=a+rcos(360°/n),y2=b+rsin(360°/n);
x3=a+rcos(2*360°/n),y2=b+rsin(2*360°/n);
x4=a+rcos(3*360°/n),y2=b+rsin(3*360°/n);
x5=a+rcos(4*360°/n),y2=b+rsin(4*360°/n);
………………………………………………………
xi=a+rcos[(i-1)*360°/n],yi=b+rsin[(i-1)*360°/n];