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What is the right way to declare of matrix whose coefficients are functions of a variable $x$ ?

I tried :

Table[Table[a[i,j][x_],{j,1,NN}],{i,1,NN}]
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  • $\begingroup$ You can not use N as a variable change it.. $\endgroup$
    – user59583
    Commented Apr 27, 2019 at 15:24
  • $\begingroup$ ok that was not the problem $\endgroup$
    – Smilia
    Commented Apr 27, 2019 at 15:26
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    $\begingroup$ What about sth. like this: Table[Table[a[i, j, x_], {j, 1, 2}], {i, 1, 2}] $\endgroup$
    – user59583
    Commented Apr 27, 2019 at 15:27
  • $\begingroup$ And what about Table[a[i, j][x_], {i, 1, NN}, {j, 1, NN}] ? Why two calls to Table ? $\endgroup$ Commented Apr 28, 2019 at 14:19

2 Answers 2

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f[x_, n_] := Table[Table[a[i, j, x], {j, 1, n}], {i, 1, n}]

for example

f[x, 4] // MatrixForm

enter image description here

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It's worth knowing about the Array function which might be used like this:

Array[a[#1, #2][x_] &, {4, 4}]

This reproduces the output of OP's initial version (with NN set to 4). I'm not convinced that that is really what OP wants, so this variation

Array[a[#1, #2, x_] &, {4, 4}]

might also appeal.

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