[交流] MATLAB计算 已有2人参与

3楼: Originally posted by 512095518 at 2017-10-16 15:15:18
参考例子：

t=;
c=;
f = @(b)b(1)*exp(-b(2)*t)-c;
f2 = @(b,t)b(1)*exp(-b(2)*t);
b0 = ;
K = lsqnonlin(f,b0);
figure
plot(t,c,'or','linewidth',2)
hold on
syms x
fplot(f2(K,x),,'linewidth',2) ...

t=[0.27 0.6 1.0 1.7 2 3 4 6];
c=[19.27 18.25 16.34 14.30 12.43 9.42 6.45 5.37];
f = @(b)b(1)*exp(-b(2)*t)-c;
f2 = @(b,t)b(1)*exp(-b(2)*t);
b0 = [0,0];
K = lsqnonlin(f,b0);
figure
plot(t,c,'or','linewidth',2)
hold on
syms x
fplot(f2(K,x),[min(t),max(t)],'linewidth',2)
R = corrcoef(c,f2(K,t));
R2 = R(2)^2;
q = legend(sprintf('R^2 = %5.4f C = %5.4f*e^{%5.4f*t}',[R2,K(1),K(2)]));
title(q,'指数拟合 C = C*\ite^{b*Z}','Color', 'r')
xlabel('c');ylabel('t');title('非线性拟合')
set(gca,'linewidth', 2, 'FontSize', 16, 'FontWeight', 'bold')