x=x0;syms xi yi af=xi2-xi*yi+3*yi2;fx=diff(f,xi);fy=diff(f,yi);fx=subs(fx,xi,yi,x0);fy=subs(fy,xi,yi,x0);fi=fx,fy;count=0;while double(sqrt(fx2+fy2)ts=-fi;if count=0elses=s1;endx=x+a*s;f=subs(f,xi,yi,x);f1=diff(f);f1=solve(f1);if f1=0ai=double(f1);breakx,f=subs(f,xi,yi,x),countx=subs(x,a,ai);fxi=diff(f,xi);fyi=diff(f,yi);fxi=subs(fxi,xi,yi,x);fyi=subs(fyi,xi,yi,x);fii=fxi,fyi;d=(fxi2+fyi2)/(fx2+fy2);s1=-fii+d*s;count=count+1;fx=fxi;fy=fyi;