“For loop” to plot graphs of functions

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HUST Student on 9 Jun 2018

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Commented: Stephen23 on 10 Jun 2018

我想写一个matlab公关(循环)代码oduce the graphs: Q as a function of A, F as a function of A, Z as a function of A from the known functions f1, f2 and f3 Z = f1 (A, F, Q) F = f2 (A, Q, Z) A = f3 (Z, Q). I made several attempts that were unsuccessful, if anyone can help me I would thank you a lot.

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HUST Student on 10 Jun 2018

                               clear
                              
                               symsw e d n A Z F Q;
                              
                               w=pi;
                              
                               e=0.5;
                              
                               d=10;
                              
                               n=1;
                              
                               eqn1 = Z+A.*w./(1-Q.*(1+e))*cos(F)==0;
                              
                               eqn2 = cos(F+2.*Q.*n.*pi)+Z.*((e-Q.*(1+e))./A.*w)==0;
                              
                               eqn3 = a - 1 /(2。* w。* abs(罪(q * n.*pi))).*(((1-e).*Z).^2+(d.*w+2.*(1+e).*(1-Q).*Q.*n.*pi.*Z).^2).^0.5==0;
                              
                               equations = [eqn1 eqn2 eqn3];
                              
                               vars = [A Z F Q];
                              
                               range = [0 10;-40 40;0 6;NaN NaN];
                              
                               forA=0:0.5:10;
                              
                               fori=1:5
                              
                               temp=vpasolve(equations, vars, range,'random', true);
                              
                               sol(i,1)=temp.Z;
                              
                               sol(i,2)=temp.F;
                              
                               sol(i,3)=temp.Q;
                              
                               end
                              
                               figure (1);
                              
                               subplot(2,2,1)
                              
                               plot(A,sol(i,1));
                              
                               xlabel('A');
                              
                               ylabel('Z');
                              
                               次要情节(2 2 2)
                              
                               plot(A,sol(i,2));
                              
                               xlabel('A');
                              
                               ylabel('F');
                              
                               subplot(2,2,3)
                              
                               plot(A,sol(i,2));
                              
                               xlabel('A');
                              
                               ylabel('Q');
                              
                               end

Error using getEqnsVars (line 50) Expecting two arguments: a vector of equations and a vector of variables.

Error in sym/vpasolve (line 95) [eqns,vars] = getEqnsVars(varargin{1:N});

Error in Sucesso (line 15) temp=vpasolve(equations, vars, range, 'random', true);

I do not know how to solve this error, because in the three equations eqn1 eqn2 eqn3 A is a variable that in the loop assumes the constant values in the interval (0, 10) so in each loop step a system of three equations with three variables (Z, Q, F) supposed to be solved. Thank.