How to Integrate a Numeric Solution to a Differential Equation in Maple?

[zeebo17]

Hi,

I have a question about integrating an numeric solution to a differential equation in Maple. I have solved a system of 3 odes:
sol := dsolve({initial, syst}, func, numeric)
where
syst := diff(OmegaLambda(x), x) = ode1, diff(OmegaK(x), x) = ode2, diff(lnH(x), x) = ode3.

This then gives me analytic solutions as a function of x to the 3 odes and I can plot, say the third solution, by defining
lnH2 := x-> rhs(op(4, sol(x)))
and plotting lnH2.

Now I want to integrate something that is a function of lnH2 with respect to x. However, I'm not sure how to do that. It doesn't seem to recognize that it is a function of x when doing:
int(exp(lnH2), x = 0 .. p).
It just thinks that exp(lnH2) is a constant.

Does anyone know what the syntax is for integrating an numeric solution??
Thanks!

 

[mmwave]

Hi there,

Thank you for your question. Integrating a numeric solution to a differential equation in Maple can be done using the "int" command. However, it is important to note that the numeric solution must be converted to a function first before it can be integrated.

To do this, you can use the "unapply" command to convert the solution to a function. For example, if your solution is stored in the variable "sol" and you want to integrate it with respect to x, you can use the following command:

int(unapply(rhs(sol), x), x = 0 .. p)

This will convert the solution to a function and then integrate it with respect to x from 0 to p.

I hope this helps. Let me know if you have any further questions.