clear all, clc;

fel=[0 0.005 -0.005];
for i= 1:3
s=[12.5 10.25 2.75]+fel(i);

p=(sum(s)/2);
A(i)=sqrt(p*(p-s(1))*(p-s(2))*(p-s(3)));

end
A

As=[]
for i =1:3
s=[12.5 10.25 2.75];
s(i)=s(i)+0.005;
p=(sum(s)/2);
As(i)=sqrt(p*(p-s(1))*(p-s(2))*(p-s(3)));
end
fel=sum(abs(A(1)-As))

