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Problem with solve command

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frank
frank on 18 Aug 2012
Closed: MATLAB Answer Bot on 20 Aug 2021
Hi everyone; I have a problem with solving a system of symbolic 5equations-5unknowns. MATLAB returns an error of "Explicit solution could not be found", however I can't recognize why?! By the way I've written my codes below:
clear all
clc
syms k1 k2 k3 m1 m2 u1 u2 a b
s1=0;
s2=0;
x=(k1+k2)/m1+(k2+k3)/m2;
y=(((k1+k2)/m1)^2+((k2+k3)/m2)^2+(2*k2^2-(k1+k3)*k2-2*k1*k3)/(m1*m2))^0.5;
omega1=(2^0.5/2)*(x+y)^0.5;
omega2=(2^0.5/2)*(x-y)^0.5;
delta=omega2-omega1;
eps=(k2)/(y*(m1*m2)^0.5);
L=eps+delta+u1*(a-(2^0.5/2)*(((x+y)^0.5)-((x-y)^0.5))+s1^2)+u2*(b-(k2/(y*(m1*m2)^0.5))+s2^2);
dldk1=jacobian(L,k1);
dldk2=jacobian(L,k2);
dldk3=jacobian(L,k3);
dldu1=jacobian(L,u1);
dldu2=jacobian(L,u2);
A=solve(dldk1,dldk2,dldk3,dldu1,dldu2,'k1,k2,k3,u1,u2');
Thanks for your help.

Answers (1)

Walter Roberson
Walter Roberson on 18 Aug 2012
I have not found documented any possibility of specifying the variables as a quoted string separated by commas. Try
A=solve(dldk1,dldk2,dldk3,dldu1,dldu2,k1,k2,k3,u1,u2);
  4 Comments
Azzi Abdelmalek
Azzi Abdelmalek on 18 Aug 2012
i don't think solve can resolve any equations, when they are very complicated
frank
frank on 18 Aug 2012
So how can I solve these kind of equations?

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