function [x,y]=cal(x1,y1,x2,y2,r1,r2)d1=x1^2-x2^2;d2=y1^2-y2^2;d3=x1-x2;d4=y1-y2;d5=r1^2-r2^2;if d3==0    y=(d5-d1-d2)/(-2*d4);    x=x1;elseif d4==0     x=(d5-d1-d2)/(-2*d3);     y=y1;    else      k=d4/d3;      a=2*(d3+d4*k);      b=2*d4*y1-2*d4*k*x1;      m=d1+d2-d5;      x=(m-b)/a;      y=k*(x-x1)+y1;end%{while x>100        x=100-(x-100);        x=abs(x);    end    while y>100       y=100-(y-100);       y=abs(y);    end%}    x=abs(x);    y=abs(y);