24小时热门版块排行榜

返回列表

浅紫微蓝

木虫 (初入文坛)

应助: 0 (幼儿园)
金币: 1684.5
散金: 50
帖子: 6
在线: 8.4小时
虫号: 1352694
注册: 2011-07-21
性别: MM
专业: 无机化工

[求助] MATLAB求解多元非线性方程组

我想求解一个非常复杂的方程组，原理很简单，就是解三个方程求出三个未知数a、b、c，但每一个方程都包含exp、log、sqrt函数，不知道能否用MATLAB求出解来，我试着写了程序，但是运行不出来，我第一次用MATLAB，不知道写的对不对，请各位高手帮忙解出该方程组来，我有急用，谢谢了~
syms a b c
I=3*a+4*b+3*c;
f=-4*0.377/1.2*I*log(1+1.2*sqrt(I));
f1=-2*0.377*(sqrt(I)/(1+1.2*sqrt(I))+2/1.2*log(1+1.2*sqrt(I)));
B1=-0.03942+0.97225/2/I*(1-(1+2*sqrt(I))*exp(-2*sqrt(I)));
B11=0.97225/2/I/I*(-1+(1+2*sqrt(I)+2*I)*exp(-2*sqrt(I)));
C1=0.0179/sqrt(8);
B2=0.23825+2.9605/0.98/I*(1-(1+1.4*sqrt(I))*exp(-1.4*sqrt(I)))-30.905/72/I*(1-(1+12*sqrt(I))*exp(-12*sqrt(I)));
B21=2.9605/0.98/I/I*(-1+(1+1.4*sqrt(I)+0.98*I)*exp(-1.4*sqrt(I)))-30.905/72/I/I*(-1+(1+12*sqrt(I)+72*I)*exp(-12*sqrt(I)));
C2=0.003;
B3=0.00488+0.4911/2/I*(1-(1+2*sqrt(I))*exp(-2*sqrt(I)));
B31=0.4911/2/I/I*(-1+(1+2*sqrt(I)+2*I)*exp(-2*sqrt(I)));
C3=-0.00116/sqrt(8);
g=(1-(1+2*sqrt(I))*exp(-2*sqrt(I)))/2/I;
g1=(-1+(1+2*sqrt(I)+2*I)*exp(-2*sqrt(I)))/2/I/I;
w=1+(I*f1-f+4*a*(a+b+c)*(B1+I*B11+4*(a+b+c)*C1)+2*b*(a+b+c)*(B2+I*B21+4*(a+b+c)*C2)+4*c*(a+b+c)*(B3+I*B31+4*(a+b+c)*C3))/(3*a+2*b+3*c);

r1=exp(f1+(4/3*a+4/3*(a+b+c))*(B1+2*(a+b+c)*C1)+4/3*c*(B3+2*(a+b+c)*C3)+2/3*b*(B2+2*(a+b+c)*C2)+2*a*(a+b+c)*(2*B11+4/3*C1)+2*c*(a+b+c)*(2*B31+4/3*C3)+b*(a+b+c)*(2*B21+4/3*C2)+8/3*c*(0.125167+1.078184*g)+4/3*b*(2.521475-15.811274*g)+(4/3*c*(a+b+c)+4/6*a*c)*(-0.0080597)+(2/3*b*(a+b+c)+1/3*a*b)*(-1.016358)+1/3*c*b*0.0672253+4*a*c*1.078184*g1+2*a*b*(-15.811274)*g1+2*c*b*10.163009*g1);

r2=exp(2*f1+(b+(a+b+c))*(B2+2*(a+b+c)*C2)+2*a*(B1+2*(a+b+c)*C1)+2*c*(B3+2*(a+b+c)*C3)+2*a*(a+b+c)*(4*B11+2*C1)+b*(a+b+c)*(4*B21+2*C2)+2*c*(a+b+c)*(4*B31+2*C3)+2*a*(2.521475-15.811274*g)+2*c*(-0.0692694+10.163009*g)+(a*(a+b+c)+1/2*a*b)*(-1.016358)+(c*(a+b+c)+1/2*b*c)*0.0672253+a*c*(-0.0080597)+4*a*b*(-15.811274)*g1+4*c*b*10.163009*g1+8*a*c*1.078184*g1);

r3=exp(f1+(4/3*c+4/3*(a+b+c))*(B3+2*(a+b+c)*C3)+4/3*a*(B1+2*(a+b+c)*C1)+2/3*b*(B2+2*(a+b+c)*C2)+2*a*(a+b+c)*(2*B11+4/3*C1)+2*c*(a+b+c)*(2*B31+4/3*C3)+b*(a+b+c)*(2*B21+4/3*C2)+8/3*a*(0.125167+1.078184*g)+4/3*b*(-0.0692694+10.163009*g)+(4/3*a*(a+b+c)+4/6*a*c)*(-0.0080597)+(2/3*b*(a+b+c)+1/3*c*b)*0.0672253+1/3*a*b*(-1.016358)+4*a*c*1.078184*g1+2*a*b*(-15.811274)*g1+2*c*b*10.163009*g1);

eq1=b*r2*(exp(-(3*a+2*b+3*c)*w/55.51))^7-0.076849;
eq2=b*c*r2*r3*(exp(-(3*a+2*b+3*c)*w/55.51))^6-0.012198;
eq3=a*r1*(exp(-(3*a+2*b+3*c)*w/55.51))^10-0.092085;
[a,b,c]=solve(eq1,eq2,eq3,'a,b,c')

回复此楼