format long;
arrayx = [0.3-0.5488 0.4-0.4493 0.5-0.3679 0.6-0.3012];
arrayy = [0.3 0.4 0.5 0.6];

d = 3;

for i=1:d+1
  L(i) = arrayy(i);
  for j=1:d+1
    if i==j
      continue;
     end;
    
    L(i) *= (0 - arrayx(j))/(arrayx(i)-arrayx(j));
    end
end

sum =0;
for i=1:d+1
  sum += L(i);
 end
 
 sum