Aproxx

clc;
clear all;
%format long;
tab=[
      1.700     4.460;
      0.510    -0.090;
      0.810    -0.790;
      0.970     0.030;
      1.100     2.040;
      1.520     4.140;
      0.110     1.000;
      1.520     4.090;
      0.110     1.030;
      0.310     1.580;
      0.970     0.110;
      0.820    -0.780;
      0.510    -0.080;
      0.810    -0.770;
      1.520     4.060;
      0.320     1.610;
      0.710    -0.780;
      0.960     0.010;
      0.700    -0.770;
      1.100     2.050]
  x=tab(:,1);
  y=tab(:,2);
n=length(x); %liczba pkt. aproksymacji
m=3;            %stopien wielomianu

S=zeros(m+1,m+2);

for i=0:m
for j=0:m
for k=0:n-1
S(i+1,j+1)=S(i+1,j+1)+(x(k+1))^(i+j);
end
end
end


for i=0:m
for j=0:n-1
S(i+1,m+2)=S(i+1,m+2)+y(j+1)*((x(j+1))^i);
end
end

[n,m]=size(S);

for i=1:n
for j=1:m-1
S1(i,j)=S(i,j);
end
end


for i=1:n
b(i)=S(i,m);
end

disp('S = ');disp(S1);
disp('b = ');disp(b');
[n,m]=size(S1);

for k=1:m
T=S1(:,k);
S1(:,k)=b';
W(k)=det(S1);
S1(:,k)=T;
end
D=det(S1)
a=W./D;
disp('Współczynniki a = ');disp(a);