这个拟合的曲线，为什​么第一条好第二条在图​例中是一样.。

这个拟合的曲线，为什么第一条好第二条在图例中是一样的呢？

d=[500 1000 1500 2000 2500];

t1=[0.299 0.566 0.841 1.117 1.393];

d.^2;

t1.^2;

scatter(d.^2,t1.^2)

hold on

p1=polyfit(d.^2,t1.^2,1);

f1=polyval(p1,d.^2);

plot(d.^2,t1.^2,'r-*')

t2=[0.364 0.517 0.701 0.897 1.099];

t2.^2;

scatter(d.^2,t2.^2)

p2=polyfit(d.^2,t2.^2,1);

f2=polyval(p2,d.^2);

plot(d.^2,f2,'b-s')

t3=[0.592 0.638 0.708 0.799 0.896];

t3.^2;

scatter(d.^2,t3.^2,[0.25 0.25 0.25])

p3=polyfit(d.^2,t3.^2,1);

f3=polyval(p3,d.^2);

plot(d.^2,t3.^2,'g-d')

legend('第一条','第二条','第三条',2)

Answer 1

[rimomov]

d=[500 1000 1500 2000 2500];

t1=[0.299 0.566 0.841 1.117 1.393];

d.^2;

t1.^2;

scatter(d.^2,t1.^2,'ro')

hold on

p1=polyfit(d.^2,t1.^2,1);

f1=polyval(p1,d.^2);

plot(d.^2,t1.^2,'r-*')

t2=[0.364 0.517 0.701 0.897 1.099];

t2.^2;

scatter(d.^2,t2.^2,'+')

p2=polyfit(d.^2,t2.^2,1);

f2=polyval(p2,d.^2);

plot(d.^2,f2,'b-s')

t3=[0.592 0.638 0.708 0.799 0.896];

t3.^2;

scatter(d.^2,t3.^2,'gv')

p3=polyfit(d.^2,t3.^2,1);

f3=polyval(p3,d.^2);

plot(d.^2,t3.^2,'g-^')

legend('第一条 (data)','第一条 (fit)','第二条 (data)','第二条 (fit)','第三条 (data)','第三条 (fit)',2)