Math Problem Statement

Write the correct properties of invertible matrices. a. If A is an invertible matrix, then (A^{-1})^{-1} = ?. b. If A is an invertible matrix and c is a nonzero scalar, then (cA)^{-1} = ?. c. If A and B are invertible matrices of the same size, then (AB)^{-1} = ?. d. If A is an invertible matrix, then (A^T)^{-1} = ?.

Solution

The image asks for filling in the correct properties of invertible matrices. Let’s go through each statement and provide the correct answers:

a. If AA is an invertible matrix, then A1A^{-1} is invertible, and (A1)1=A(A^{-1})^{-1} = A.

b. If AA is an invertible matrix and cc is a nonzero scalar, then cAcA is an invertible matrix, and (cA)1=1cA1(cA)^{-1} = \frac{1}{c}A^{-1}.

c. If AA and BB are invertible matrices of the same size, then ABAB is invertible, and (AB)1=B1A1(AB)^{-1} = B^{-1}A^{-1}.

d. If AA is an invertible matrix, then ATA^T (the transpose of AA) is invertible, and (AT)1=(A1)T(A^T)^{-1} = (A^{-1})^T.

Would you like further details on any of these properties?

Here are five related questions to further expand your understanding:

  1. What are the conditions under which a matrix is invertible?
  2. How does the determinant of a matrix relate to its invertibility?
  3. Can the inverse of a non-square matrix exist?
  4. How do these properties extend to block matrices?
  5. What happens when you invert a matrix product involving more than two matrices?

Tip: Remember that matrix multiplication is generally not commutative, meaning ABBAAB \neq BA in most cases, which is why the order of inverses matters.

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Math Problem Analysis

Mathematical Concepts

Matrix Algebra
Inverse Matrices
Matrix Transposition
Scalar Multiplication

Formulas

(A^{-1})^{-1} = A
(cA)^{-1} = (1/c)A^{-1}
(AB)^{-1} = B^{-1}A^{-1}
(A^T)^{-1} = (A^{-1})^T

Theorems

Properties of Invertible Matrices
Matrix Multiplication
Transpose and Inverse Theorems

Suitable Grade Level

Undergraduate or Advanced High School (Grades 11-12)