matlab高手进! 插值与拟合答:y=[-2.86,-2.09,-2.26,-1.09,0.75,1.80,1.56,0.40,1.63,2.15];xi=linspace(0,9,20);yi=interp1(x,y,xi,'linear');yii=interp1(x,y,xi,'spline');plot(x,y,'o',xi,yi,'-');hold on;plot(xi,yii,'r');hold on;yt=polyfit(x,y,2);yt1=polyval(yt,xi);pl...