%求三個圓所相交部分的三個交點坐標(fn1x,fn1y),(fn2x,fn2y),(fn3x,fn3y)
%三個圓(圓心為x1,y1半徑為r1。圓心為x2,y2半徑為r2。圓心為x3,y3半徑為r3)
function [fn1x,fn1y,fn2x,fn2y,fn3x,fn3y]=c3point(x1,y1,r1,x2,y2,r2,x3,y3,r3)
    %求第一個交點坐標
    [rp1x,rp1y,rp2x,rp2y]=c2point(x1,y1,r1,x2,y2,r2);
    if dist(rp1x,rp1y,x3,y3)<dist(rp2x,rp2y,x3,y3)
        fn1x=rp1x;
        fn1y=rp1y;
    else
        fn1x=rp2x;
        fn1y=rp2y;
    end
    %求第二個交點坐標
    [rp1x,rp1y,rp2x,rp2y]=c2point(x1,y1,r1,x3,y3,r3);
    if dist(rp1x,rp1y,x2,y2)<dist(rp2x,rp2y,x2,y2)
        fn2x=rp1x;
        fn2y=rp1y;
    else
        fn2x=rp2x;
        fn2y=rp2y;
    end
    %求第三個交點坐標
    [rp1x,rp1y,rp2x,rp2y]=c2point(x2,y2,r2,x3,y3,r3);
    if dist(rp1x,rp1y,x1,y1)<dist(rp2x,rp2y,x1,y1)
        fn3x=rp1x;
        fn3y=rp1y;
    else
        fn3x=rp2x;
        fn3y=rp2y;
    end