x=[0.1 0.3 0.6] 

y=[-0.2 0 0.6] 

plot(x,y,'*') 

p2=polyfit(x,y,2) 

polyval(p2,0.36) 

x0=linspace(0,1,100); 

y2=polyval(p2,x0); 

plot(x,y,'*') 

hold on 

plot(x0,y2) 

plot(x0,y2) 

plot(x0,y2) 

x=-2:1:5 

y=exp(x) 

plot(x,y) 

x0=linspace(-2.5,5.5,100); 

e0=exp(x0); 

plot(x0,y0) 

plot(x0,e0) 

p7=polyfit(x,y,7) 

y7=polyval(p7,x0); 

hold on 

plot(x0,y7) 

plot(x0,y7). 

plot(x0,y7)