Math Problem Statement

in the situation C^-1 = {(1,2),(3,4)} and B = {(5,6),(7,8)} please solve [I]BC=C^-1 B

Solution

We are tasked to solve the matrix equation:

[I]BC=C1B[I]BC = C^{-1}B

where:

  • C1={(1,2),(3,4)}C^{-1} = \{(1,2), (3,4)\},
  • B={(5,6),(7,8)}B = \{(5,6), (7,8)\},
  • [I][I] is the identity matrix.

Step 1: Represent C1C^{-1} and BB as matrices

C1=[1234],B=[5678].C^{-1} = \begin{bmatrix} 1 & 2 \\ 3 & 4 \end{bmatrix}, \quad B = \begin{bmatrix} 5 & 6 \\ 7 & 8 \end{bmatrix}.

Step 2: Compute C1BC^{-1}B

Multiply C1C^{-1} and BB: C1B=[1234][5678].C^{-1}B = \begin{bmatrix} 1 & 2 \\ 3 & 4 \end{bmatrix} \begin{bmatrix} 5 & 6 \\ 7 & 8 \end{bmatrix}.

Perform the multiplication:

= \begin{bmatrix} 19 & 22 \\ 43 & 50 \end{bmatrix}.$$ ### Step 3: Represent $$[I]BC$$ Since $$[I]$$ is the identity matrix, $$[I]BC = BC$$. Therefore: $$BC = \begin{bmatrix} 5 & 6 \\ 7 & 8 \end{bmatrix} \begin{bmatrix} 1 & 2 \\ 3 & 4 \end{bmatrix}.$$ Compute $$BC$$: $$BC = \begin{bmatrix} (5)(1) + (6)(3) & (5)(2) + (6)(4) \\ (7)(1) + (8)(3) & (7)(2) + (8)(4) \end{bmatrix} = \begin{bmatrix} 23 & 34 \\ 31 & 46 \end{bmatrix}.$$ ### Step 4: Compare $$[I]BC$$ and $$C^{-1}B$$ From the calculations: - $$[I]BC = BC = \begin{bmatrix} 23 & 34 \\ 31 & 46 \end{bmatrix}$$, - $$C^{-1}B = \begin{bmatrix} 19 & 22 \\ 43 & 50 \end{bmatrix}$$. Clearly, $$[I]BC \neq C^{-1}B$$. Therefore, the equation is **not satisfied**. --- ### Would you like additional details or have any questions? Here are related questions to explore: 1. How do we verify if a given matrix is invertible? 2. What properties do matrix products like $$C^{-1}B$$ satisfy? 3. Can you explain how the identity matrix interacts with other matrices? 4. Why is matrix multiplication not commutative, and how does it affect this problem? 5. How do eigenvalues relate to matrix inverses? **Tip:** Always check dimensions before performing matrix multiplication to ensure compatibility!

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Math Problem Analysis

Mathematical Concepts

Matrix Algebra
Matrix Multiplication
Inverse Matrices
Identity Matrix

Formulas

Matrix multiplication: (AB)_{ij} = Σ_k A_{ik}B_{kj}
Inverse matrix property: C * C^-1 = I

Theorems

Matrix Multiplication Associativity: (AB)C = A(BC)
Non-commutativity of Matrix Multiplication: AB ≠ BA in general

Suitable Grade Level

Undergraduate (Introductory Linear Algebra)