function?charpt3
x=-1:0.5:2;
y=[-4.447?-0.452?0.551?0.048?-0.447?0.549?4.552];
n=3;???????????????%三次擬合多項(xiàng)式
p=polyfit（xyn）;??%三次擬合多項(xiàng)式的系數(shù)
y1=polyval（px）;???%擬合多項(xiàng)式條件下給定節(jié)點(diǎn)處的函數(shù)值
r=（y1-y）*（y1-y）‘;?%平方誤差?y是實(shí)驗(yàn)所得函數(shù)值??
x0=-1.0:0.01:2.0;
y0=polyv