Trying to code from polymath

Im supposed to turn this Polymath code into a Matlab code but Im not sure how. Please help. Its supposed show a graph like in the example.

[Walter Roberson]

What happened when you followed my suggestion to set up the equations using the Symbolic Toolbox and then use the sequence shown in the odeFunction() documentation ?

Answer 1

[Walter Roberson]

I suggest that you set up the equations using the Symbolic Toolbox, and that you then use the flow of control shown in the first example for odeFunction() to convert into something that you can use with ode45()

[Walter Roberson]

Use syms to declare all of the non-constants. On the syms command line, declare each of the functions in function form, such as

syms X(V) T(V) Ta(V)

Now assign all of the constants and non-differential equations as variables, including for example

deltaH = 80770+delCp*(T-298)

Now define variables corresponding to all of the derivatives, such as

dX = diff(X, V)

For future reference: if you had second derivatives, you would take the derivative of the derivative, such as

d2X = diff(dX, V)

Now create equations such as

eqn1 = dX == -ra/Fao

You will have three equations.

Also define equations for the initial conditions, such as

IC1 = X(0) == -1
IC2 = dX(0) == 2

Create a vector of differential equations, and one of initial conditions

eqn = [eqn1; eqn2; eqn3]
ICs = [IC1; IC2; IC3]

Now follow the work flow shown in the documentation for odeFunction().

The diagram you posted does not appear to have initial conditions for the equations, and unfortunately without initial conditions you are not going to be able to re-create the plots.