huke1.m

matlab讲义

x=[1 2 4 7 9 12 13 15 17];
f=[1.5 3.9 6.6 11.7 15.6 18.8 19.6 20.6 21.1];
plot(x,f,'+'),
pause
 
x1=[1 2 4 7 9 ];
f1=[1.5 3.9 6.6 11.7 15.6 ];
k=x1'\f1';
xx1=0:0.1:9;
y1=k*xx1;
y10=k*9;
plot(x1,f1,'+',xx1,y1),
pause

x2=[9 12 13 15 17];
f2=[15.6 18.8 19.6 20.6 21.1];
u=f2-k*9;
r1=x2.^2-81;
r2=x2-9;
R=[r1' r2'];
a=R\u';
a1=a(1);a2=a(2);
xx2=9:0.1:17;
y2=a1*(xx2.^2-81)+a2*(xx2-9)+k*9;
y20=k*9;
dy20=2*a1*9+a2;
plot(x2,f2,'+',xx2,y2),
k,y10,y20,dy20,a1,a2,
pause
plot(xx1,y1,xx2,y2,x,f,'+')