# MATLAB: What was that problem

Matlab：edit，then add the the following values in a m.file
    %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%    function dx=myfun(t,x)    dx(1)=-6*x(2)*x(2)-9;    dx(2)=-3*x(1)*x(2)-2*x(3)-Yvv-Yuu;    dx(3)=x(1)*x(2)+x(3)+8;    Yvv=0.5*p*L*T*(0.048265-6.293*(1-c)*T/B);    Yuu=0.5*p*L*L*L*T*(0.0045-0.445*(1-c)*T/B);    dx=dx(:);    %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
Finally,， Matlab ：
    clear all    clc    syms Yvv Yuu p L T c T B     x0=[1,1,1];    t0=0:0.1:2;    [t,x]=ode45('myfun',[0,10],x0);  %ode45会自动调整步长    plot(t,x)     legend('u','v','Y')

      %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%      function dx=myfun(t,x)      p=1;      L=1;      T=1;      c=1;      B=1;      Yvv=0.5*p*L*T*(0.048265-6.293*(1-c)*T/B);      Yuu=0.5*p*L*L*L*T*(0.0045-0.445*(1-c)*T/B);      dx(1,1)=-6*x(2)*x(2)-9;      dx(2,1)=-3*x(1)*x(2)-2*x(3)-Yvv-Yuu;      dx(3,1)=x(1)*x(2)+x(3)+8;      %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%      clear all      clc      x0=[1,1,1];      t0=0:0.1:2;      [t,x]=ode45('myfun',[0,10],x0);  %ode45会自动调整步长      plot(t,x)       legend('u','v','Y')