# Solve coupled PDE

**URL:** <https://community.freefem.org/t/solve-coupled-pde/1728>\
**Category:** General Discussion\
**Created:** [May 10, 2022, 11:14am UTC](https://community.freefem.org/t/solve-coupled-pde/1728 "2022-05-10T11:14:03Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![MAS-OUD](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.freefem.org/mas-oud/32/1138_2.png) [@MAS-OUD](https://community.freefem.org/u/MAS-OUD)\
**Post date:** [May 10, 2022, 11:14am UTC](https://community.freefem.org/t/solve-coupled-pde/1728/1 "2022-05-10T11:14:03Z")

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Hello. How can I input the following problem in FREEFEM?

![weak](https://canada1.discourse-cdn.com/flex030/uploads/freefem/original/2X/3/379f588edd3e241a186c4aa301694b853e13b677.png)

It is actually a coupled PDE, and the coefficients in the weak form are matrices instead of scalars.

Thanks in advance

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**Author:** ![frederichecht](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.freefem.org/frederichecht/32/15_2.png) [@frederichecht](https://community.freefem.org/u/frederichecht)\
**Post date:** [May 11, 2022, 7:28am UTC](https://community.freefem.org/t/solve-coupled-pde/1728/2 "2022-05-11T07:28:28Z")

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You have no problem to use freefem++ to solve numerical this problem if you have amesh of \mathcal D not to fine.

I takes 1/3 a hours to write a first solution.