hi guys, i am having a problem with coupled differential equation i dont know where i am going wrong. pls have a look at my code and post some suggestions..

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Ajayarvindakumarr Balraj 2012-11-19

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https://ww2.mathworks.cn/matlabcentral/answers/54124-hi-guys-i-am-having-a-problem-with-coupled-differential-equation-i-dont-know-where-i-a

关闭： MATLAB Answer Bot 2021-8-20

     function d =  fun1(t,T)
      f = 0.0001;  % area of sensor
      rosoil = 0.001;
      lamdasoil = 0.55;
      alphaCon = (lamdasoil / (rosoil /2));
      Ks = ( alphaCon * f);
      p = 1300; 
      Cp = 600;      
      Csoil = (f * rosoil * Cp * p);
         Em_ast = 0.9;       
         sigma = 5.670*10^-8; 
         Em_sensor = 0.9;     
         alphas = 0.2;       
        Ta = 328;             
        qs_cosfi_sd = 0;    
       Fs  = (0.25 * 0.29);
        b = ((1/((1/Em_ast)+(((1/Em_sensor)-1)*(f/Fs)))));  
       d(1) = (((qs_cosfi_sd)*(alphas*f))-((b)*(f*sigma*(((T(1))^4)-(Ta^4))))+ (Ks*(T(1)-T(2))))/(Csoil);
       d(2) = ((Ks*(T(1)-T(2)))+(Ks*(T(2)- T(3))))/(Csoil);
       d(3) = ((Ks*(T(2)-T(3)))+(Ks*(T(3)-T(4))))/(Csoil);
       d(4) = (Ks*(T(3)-T(4)))/(Csoil);
       d = [ d(1); d(2);d(3);d(4)];
     %%%[t d]=ode45('asteroid',[0 3600],173);