令:
x1=1.2.^x; x2=1.07.^x; x3=1.1.^x;
則,y = c1 * x1 + c2 * x2 + c3 * x3;
按照最小二乘法,有:
x=[0 1 2 3 4 5]
y=[87.89 87.12 81.07 80.61 81.26 74.84]
x1=1.2.^x; x2=1.07.^x; x3=1.1.^x;
A=[sum(x1.^2), sum(x1.*x2), sum(x1.*x3)
sum(x1.*x2), sum(x2.^2), sum(x2.*x3)
sum(x1.*x3), sum(x2.*x3), sum(x3.^2) ];
b=[sum(y.*x1); sum(y.*x2); sum(y.*x3)];
cc=inv(A'*A)*A'*b;
最終的cc 就是 [c1,c2,c3]
多元壹次擬合比非線性擬合函數更加穩定直觀。
這個問題考的不是MATLAB的知識,而是看妳對最小二乘法的理解。