If I want to multiply the above 3 matrices, then I only need to find the top-right, and the entry below it in the inverse matrix (as all others will be zero).

How do I go about finding only a few entries in a large inverted matrix like this?

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- Dec 10th 2008, 01:33 AMbumcheekcityGet just a few values of invertible matrix

If I want to multiply the above 3 matrices, then I only need to find the top-right, and the entry below it in the inverse matrix (as all others will be zero).

How do I go about finding only a few entries in a large inverted matrix like this? - Dec 10th 2008, 12:31 PMOpalg
Call the matrix S, and let . If then . if then the equation becomes . That gives you five easily solved equations telling you that .

The expression then becomes . - Dec 10th 2008, 01:59 PMCaptainBlack