Metoda celor mai mici patrate
Dandu-se punctele
(0, -4), (1, 0), (2, 4), (3, -2)
determinati polinomul de gradul I corespunzator acestor date prin metoda celor mai mici patrate.
x=0:3;
y=[-4,0,4,-2];
Construim design matrix si determinam coeficientii
X=[ones(4,1),x'];
c=X\y'
Reprezentam grafic punctele si aproximanta
t=linspace(-1,4,10);
ty=c(1)+c(2)*t;
plot(x,y,'o',t,ty,'MarkerFaceColor','blue')
Ecuatiile normale
B=X'*X
X'*y'
[Q,R]=qr(X)
[Q2,R2]=qr(X,0)