You can enter coefficients for a system with N = 2 equations in the PDE app, see Systems of PDEs. To do so, open the PDE app and select Generic System.
Then select PDE > PDE Specification.
Enter string expressions for coefficients using the form in Coefficients for Scalar PDEs in PDE App, with additional options for nonlinear equations. The additional options are:
Represent the ith component of the solution u using 'u(i)' for i = 1 or 2.
Similarly, represent the ith components of the gradients of the solution u using 'ux(i)' and 'uy(i)' for i = 1 or 2.
Do not use quotes or unnecessary spaces in your entries.
For higher-dimensional systems, do not use the PDE app. Represent your problem coefficients at the command line.
You can enter scalars into the c matrix, corresponding to these equations:
If you need matrix versions of any of the cij coefficients, enter expressions separated by spaces. You can give 1-, 2-, 3-, or 4-element matrix expressions. These mean:
For details, see c for Systems.
For example, these expressions show one of each type (1-, 2-, 3-, and 4-element expressions)
These expressions correspond to the equations