solve not outputting an answer

Question

ben howey 2017-3-20

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/330927-solve-not-outputting-an-answer

评论： Walter Roberson 2017-3-21

I am trying to solve 6 non linear equation with 6 unknowns using the symbolic method. When I run the following script, it just stays on busy and does not return any values. Can anyone help?!

lAB=0.35;
lBC=0.257;
lCD=0.995;
dX=1.4;
dz=0.5;
Mmw=0.5;
rhomw=11340;
Mmb=0.116E-3;
rhomb=14;
Fmw=Mmw*9.81;
Fmb=Mmb*9.81;
syms T1 T2 T3 a1 a2 a3
sol=solve([T1*cos(a1)-T2*cos(a2)==0,...
    T2*cos(a2)-T3*cos(a3)==0,T1*sin(a1)+T2*sin(a2)-Fmw==0,...
    Fmb-T2*sin(a2)-T3*sin(a3)==0,lAB*cos(a1)+lBC*cos(a2)+lCD*cos(a3)==dX,...
    lAB*sin(a1)+lBC*sin(a2)+lCD*sin(a3)==dz],[T1,T2,T3,a1,a2,a3]);

Thanks

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ben howey 2017-3-20

编辑：Walter Roberson 2017-3-20

在 MATLAB Online 中打开

I have also tried using the numerical solver fsolve as follows and it returns an error and won't run at all.

function F = angsystem(x,lAB,lBC,lCD,dX,dz,Fmw,Fmb)
F(1)=x(1)*cos(x(2))-x(3)*cos(x(4));
F(2)=x(3)*cos(x(4))-x(5)*cos(x(6));
F(3)=x(1)*sin(x(2))+x(3)*sin(x(4))-Fmw;
F(4)=Fmb-x(3)*sin(x(4))-x(5)*sin(x(6));
F(5)=lAB*cos(x(2))+lBC*cos(x(4))+lCD*cos(x(6))-dX;
F(6)=lAB*sin(x(2))+lBC*sin(x(4))+lCD*sin(x(6))-dz;
%%%%%%%.m Script
lAB=0.35;
lBC=0.257;
lCD=0.995;
dX=1.4;
dz=0.5;
Mmw=0.5;
rhomw=11340;
Mmb=0.116E-3;
rhomb=14;
Fmw=Mmw*9.81;
Fmb=Mmb*9.81;
fun=@angsystem;
x0=[20,20,20,0,0,0];
x=fsolve(fun,x0)

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Answer 1

Walter Roberson 2017-3-20

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/330927-solve-not-outputting-an-answer#answer_259572

在 MATLAB Online 中打开

%%%%%%%.m Script
lAB=0.35;
lBC=0.257;
lCD=0.995;
dX=1.4;
dz=0.5;
Mmw=0.5;
rhomw=11340;
Mmb=0.116E-3;
rhomb=14;
Fmw=Mmw*9.81;
Fmb=Mmb*9.81;
fun=@(x) angsystem(x,lAB,lBC,lCD,dX,dz,Fmw,Fmb);
x0=[20,20,20,0,0,0];
[x, fval] = fsolve(fun,x0)