function F=myfun(x)
xx=[-2.26 -1.83 -1.46];
yy=[1.91 1.51 1.88];
z=-41.720;
F=[(x(4)*xx(1)/(x(1)*xx(1)+x(2)*yy(1)+x(3)*z)-x(5))^2+(x(4)*yy(1)/(x(1)*xx(1)+x(2)*yy(1)+x(3)*z)-x(6))^2+(x(4)*z/(x(1)*xx(1)+x(2)*yy(1)+x(3)*z)-x(7))^2-1;
    (x(4)*xx(2)/(x(1)*xx(2)+x(2)*yy(2)+x(3)*z)-x(5))^2+(x(4)*yy(2)/(x(1)*xx(2)+x(2)*yy(2)+x(3)*z)-x(6))^2+(x(4)*z/(x(1)*xx(2)+x(2)*yy(2)+x(3)*z)-x(7))^2-1;
    (x(4)*xx(3)/(x(1)*xx(3)+x(2)*yy(3)+x(3)*z)-x(5))^2+(x(4)*yy(3)/(x(1)*xx(3)+x(2)*yy(3)+x(3)*z)-x(6))^2+(x(4)*z/(x(1)*xx(3)+x(2)*yy(3)+x(3)*z)-x(7))^2-1;
    x(1)^2+x(2)^2+x(3)^2-1];