Challenge Problems for Chapter 7

Consider the matrix Does there exist a value of for which this matrix fails to have an inverse? Explain.

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If and are each matrices and is invertible, show why each of and are invertible.

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Suppose are matrices and that Show that then
Suppose is an upper triangular matrix. Show that exists if and only if all elements of the main diagonal are non zero. Is it true that will also be upper triangular? Explain. Could the same be concluded for lower triangular matrices?
Let , , and denote matrices. Assume that , , and . Evaluate
(a)
(b)
(c)
If and are matrices such that , and if is odd, show that either or has no inverse.
Show that no matrix exists such that . Find a matrix with this property.
Show that for any matrices and .

Bibliography

These problems come from Chapter 3 of Ken Kuttler’s A First Course in Linear Algebra. (CC-BY)

Ken Kuttler, A First Course in Linear Algebra, Lyryx 2017, Open Edition, pp. 272–315.

Several problems came from the end of Chapter 3 of Keith Nicholson’s Linear Algebra with Applications. (CC-BY-NC-SA)

W. Keith Nicholson, Linear Algebra with Applications, Lyryx 2018, Open Edition, pp. 167.

2024-09-06 23:46:28