%u minmizes E(u, lambda) over set l0=integral(u)=c
function E_0 = areaConstraint(u,~)
lambda=[ 1; 0.5; 0.3; 1.5; 0.6; 1; 1.8; 2; 0.2; 0.16; 1.4; 2];
n= lambda(1);
E_0(u,n)=sum(int(f(x)).*u,int(g(x)).* abs(Du(x)))+n.*(int(u)-c).^2;