- Write a function that defines the rate equations. The system should now look like z' = f(c,z), where z = [A;v]. Write your function file so that it takes c and a vector z as inputs, and returns a vector dz that represents the derivatives ([A';v'])
- Use ode45 to solve the system, giving a function handle to you function from step 2 as input, as well as the vector of start and end values for c and the initial conditions z0 = [A0;v0].
- Extract the components of the solution returned by ode45 to plot as a function of c (also returned by ode45). (If A and v are on the same scale, you could just do plot(c,z))
Basic ODE question
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Seth
le 4 Mar 2011
Réponse apportée : jagathi medempudi
le 27 Août 2020
So...it's been quite a while since I solved any systems of ODEs and I am admittedly very rusty. I am hoping there is a simple answer to this question:
I have a coupled system of ODEs:
dA/dc=-0.5*(2-v)*(1-v^2)/(1-v)
and
dv/dc=-1.5*(5-v)*(1-v^2)/(3-v)
Solve from c=[0 1]
Initial conditions: Ao=100, vo=0.5
How can I set this up in a Matlab function? Thanks for any advice!
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Réponse acceptée
Matt Tearle
le 5 Mar 2011
Your question is mainly about step 1. So write a function file
function dz = functionname(c,z)
dz = zeros(size(z));
% extract components of z (ie A & c)
% define dz(1) according to the equation for dA/dc
% define dz(2) according to the equation for dv/dc
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Plus de réponses (3)
SHOBHIT KUMAR
le 9 Juin 2019
can we not just do this and find the solution from gtaph and get the answer?
sol=dsolve('Da=-0.5*(2-v)*(1-v^2)/(1-v)','a(0)=100','c');
ezplot(sol,[-2 2])
hold on;
s=dsolve('Dv=-1.5*(5-v)*(1-v^2)/(3-v)','v(0)=0.5','c');
ezplot(s,[-2 2])
Please answer
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jagathi medempudi
le 27 Août 2020
What is the mat lab command for solving differential equation
Select one:
a. differentiation
b. dsolve
c. int
d. diff
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