Chapter 2: Problem 70
Write \(A=\left[\begin{array}{ll}4 & 5 \\ 1 & 3\end{array}\right]\) as the sum of a symmetric matrix \(B\) and a skew-symmetric matrix \(C\).
/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none}
Learning Materials
Features
Discover
Chapter 2: Problem 70
Write \(A=\left[\begin{array}{ll}4 & 5 \\ 1 & 3\end{array}\right]\) as the sum of a symmetric matrix \(B\) and a skew-symmetric matrix \(C\).
All the tools & learning materials you need for study success - in one app.
Get started for free
Suppose \(A B=C,\) where \(A\) and \(C\) are upper triangular. (a) Find \(2 \times 2\) nonzero matrices \(A, B, C,\) where \(B\) is not upper triangular. (b) Suppose \(A\) is also invertible. Show that \(B\) must also be upper triangular.
Let \(V\) and \(W\) be vector spaces with subspaces \(V_{1}\) and \(W_{1}\), respectively. If \(\mathrm{T}: \mathrm{V} \rightarrow \mathrm{W}\) is linear, prove that \(\mathrm{T}\left(\mathrm{V}_{1}\right)\) is a subspace of \(\mathrm{W}\) and that $\left\\{x \in \mathrm{V}: \mathrm{T}(x) \in \mathrm{W}_{1}\right\\}\( is a subspace of \)\mathrm{V}$.
Suppose \(A\) is a square matrix. Show (a) \(A+A^{T}\) is symmetric, (b) \(A-A^{T}\) is skew-symmetric, (c) \(A=B+C,\) where \(B\) is symmetric and \(C\) is skew- symmetric.
Label the following statements as true or false. Assume that \(V\) and \(\mathrm{W}\) are finite-dimensional vector spaces with ordered bases \(\beta\) and \(\gamma\), respectively, and $\mathrm{T}, \mathrm{U}: \mathrm{V} \rightarrow \mathrm{W}$ are linear transformations. (a) For any scalar \(a, a \mathbf{T}+\mathbf{U}\) is a linear transformation from \(\mathbf{V}\) to \(\mathbf{W}\). (b) \([\mathrm{T}]_{\beta}^{\gamma}=[\mathrm{U}]_{\beta}^{\gamma}\) implies that \(\mathrm{T}=\mathrm{U}\). (c) If \(m=\operatorname{dim}(\mathrm{V})\) and \(n=\operatorname{dim}(\mathrm{W})\), then \([\mathrm{T}]_{\beta}^{\gamma}\) is an \(m \times n\) matrix. (d) \([\mathrm{T}+\mathrm{U}]_{\beta}^{\gamma}=[\mathrm{T}]_{\beta}^{\gamma}+[\mathrm{U}]_{\beta}^{\gamma}\). (e) \(\mathcal{L}(\mathrm{V}, \mathrm{W})\) is a vector space. (f) \(\mathcal{L}(\mathrm{V}, \mathrm{W})=\mathcal{L}(\mathrm{W}, \mathrm{V})\).
Refer to the following matrices: $$A=\left[\begin{array}{rrr} 1 & -1 & 2 \\ 0 & 3 & 4 \end{array}\right], \quad B=\left[\begin{array}{rrr} 4 & 0 & -3 \\ -1 & -2 & 3 \end{array}\right], \quad C=\left[\begin{array}{rrrr} 2 & -3 & 0 & 1 \\ 5 & -1 & -4 & 2 \\ -1 & 0 & 0 & 3 \end{array}\right], \quad D=\left[\begin{array}{rr} 2 \\ -1 \\ 3 \end{array}\right].$$ Find (a) \(3 A-4 B,\) (b) \(A C,\) (c) \(B C,\) (d) \(A D,\) (e) \(B D,\) (f) \(C D.\)
What do you think about this solution?
We value your feedback to improve our textbook solutions.