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Topic: Integrating a Matrix
Replies: 6   Last Post: Nov 29, 2013 3:48 AM

 Messages: [ Previous | Next ]
 Bob Hanlon Posts: 906 Registered: 10/29/11
Re: Integrating a Matrix
Posted: Nov 28, 2013 2:16 AM

tab = Table[f[i, j][x], {i, 3}, {j, 3}]

Integrate[tab, {x, 0, 1}]

tab2 = tab /. f[i_, j_][x_] -> (i + j) x^i

{{2*x, 3*x, 4*x}, {3*x^2,
4*x^2, 5*x^2}, {4*x^3,
5*x^3, 6*x^3}}

Integrate[tab2, {x, 0, 1}]

{{1, 3/2, 2}, {1, 4/3, 5/3},
{1, 5/4, 3/2}}

NIntegrate[tab2, {x, 0, 1}]

{{1., 1.5, 2.}, {1., 1.33333, 1.66667}, {1., 1.25, 1.5}}

Bob Hanlon

On Wed, Nov 27, 2013 at 1:24 AM, David Barnes <barnes@pullman.com> wrote:

> I have a 3X3 matrix of functions fij[x], for i,j = 1,2,3, and I want to
> NIntegrate all nine elements over 0<x<1 to get a matrix of constants. Is
> there an easy way to do this other that doing 9 individual NIntegration's?
>
>

Date Subject Author
11/28/13 Bob Hanlon
11/28/13 Murray Eisenberg