Monthly Archives: April 2011

Linear Algebra and Its Applications, Exercise 1.6.11

Posted on April 9, 2011 by hecker

Exercise 1.6.11. For each of the following criteria, give examples of matrices A and B that satisfy the criteria: (i) Both A and B are invertible, but their sum A+B is not invertible. (ii) Neither A nor B is invertible, … Continue reading →

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Multiplying block matrices

Posted on April 7, 2011 by hecker

In doing exercise 1.6.10 in Linear Algebra and Its Applications I was reminded of the general issue of multiplying block matrices, including diagonal block matrices. This also came up in exercise 1.4.24 as well, which I answered without necessarily fully … Continue reading →

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Linear Algebra and Its Applications, Exercise 1.6.10

Posted on April 6, 2011 by hecker

Exercise 1.6.10. Determine the inverses of the following matrices: Answer: The first matrix has the form of a diagonal matrix, only flipped horizontally, and it’s therefore worth seeing if its inverse has an analogous form to the inverse of a … Continue reading →

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