clear
clc
syms x y z L
f(x,y,z)=x^2+y^2+z^2;
g(x,y,z)=3*x^2+4*x*y+6*y^2-140;
F=f+L*g;
Fx=diff(F,x);
Fy=diff(F,y);
Fz=diff(F,z);
S=solve(g,Fx,Fy,Fz,'Real',true);
St_pts=[S,x,S,y,S,z];
St_pts=double(St_pts)
Fun_Val=f(S,x,S,y,S,z);
Fun_Val=double(Fun_Val);