Defining function file of ODE function

Question

Carey n'eville 2020-11-23

0
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https://ww2.mathworks.cn/matlabcentral/answers/658703-defining-function-file-of-ode-function

评论： Carey n'eville 2020-11-23

%We have initial concentration C(0)=5, but I didn't understand how I use this value and also my code does'nt work.
function dCdt=Conc(C,t)
  global t;
  global C;
k1=0.7;
t=0:1:6;
Vo=1;
Q=Vo;
Cin=200;
  dCdt=-(k1+(t/(Vo+Q*t)))*C+((Q*Cin)/(Vo+Q*t));
end
%I get this error, Could you help to me, please:
%Error using  / 
%Matrix dimensions must agree.
%Error in Conc (line 10)
%  dCdt=-(k1+(t/(Vo+Q*t)))*C+mrdivide((Q*Cin),(Vo+Q*t));
 

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Answer 1

Stephan 2020-11-23

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/658703-defining-function-file-of-ode-function#answer_553223

编辑：Stephan 2020-11-23

在 MATLAB Online 中打开

C0 = 5;
tspan = [0 10];
[t,C] = ode45(@Conc,tspan,C0);
plot(t,C)
function dCdt=Conc(t,C)
k1=0.7;
Vo=1;
Q=Vo;
Cin=200;
dCdt=-(k1+(t./(Vo+Q.*t)))*C+((Q*Cin)/(Vo+Q.*t));
end