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Re: derivative of matrix in mathematica

• To: mathgroup at smc.vnet.net
• Subject: [mg120156] Re: derivative of matrix in mathematica
• From: Heike Gramberg <heike.gramberg at gmail.com>
• Date: Sun, 10 Jul 2011 05:01:51 -0400 (EDT)
• References: <201107091132.HAA13492@smc.vnet.net>

You could do something like

n = 3;
matrix := Table[p[i, j][#], {i, 1, n}, {j, 1, n}] &

then matrix'[t] gives

{{Derivative[1][p[1, 1]][t], Derivative[1][p[1, 2]][t],
  Derivative[1][p[1, 3]][t]}, {Derivative[1][p[2, 1]][t],
  Derivative[1][p[2, 2]][t],
  Derivative[1][p[2, 3]][t]}, {Derivative[1][p[3, 1]][t],
  Derivative[1][p[3, 2]][t], Derivative[1][p[3, 3]][t]}}

To set each of the elements of this matrix equal to the elements of another matrix
you can do something like

MapThread[
  SetDelayed, {matrix[t_], Table[Sin[i t] j, {i, 1, n}, {j, 1, n}]}, 2];

Heike

On 9 Jul 2011, at 12:32, yashar wrote:

> hi
> in mathematica
> how i can produce a general n by n matrix so that each of its elements be a variable of t???
> how i can take derivative of this matrix with respect to variable t?
> how i can with equating this n by n matrix with another n by n matrix which its elements are known obtain unknown elements of this general n by n matrix?
>

• References:
  • derivative of matrix in mathematica
    • From: yashar <physics1389@yahoo.com>