Math Problem Statement

Given two matrices A and B, find the element C_1^2 of the matrix C = A · B. The upper index corresponds to the row number.

Solution

The problem involves matrix multiplication C=ABC = A \cdot B, where the matrices AA and BB are given. The task is to find the specific element C12C_1^2 of the resulting matrix CC. The element C12C_1^2 corresponds to the element in the first row and second column of the product CC.

Steps to Solve:

  1. Matrix Multiplication: Calculate C=ABC = A \cdot B using the formula for the elements of the resulting matrix CC: Cij=kAikBkj.C_{ij} = \sum_{k} A_{ik} \cdot B_{kj}.

  2. Focus on C12C_1^2: To find C12C_1^2, compute the dot product of the first row of AA with the second column of BB.

Matrices:

\begin{bmatrix} 3 & -3 & 1 & -3 \\ 4 & 0 & 5 & -1 \\ 4 & 0 & 4 & -2 \end{bmatrix}, \quad B = \begin{bmatrix} 3 & -3 & 1 & -1 \\ 4 & -1 & 5 & 0 \\ 1 & -2 & 2 & 1 \\ 5 & 0 & 3 & -2 \end{bmatrix}.$$ ### First Row of $$A$$: $$[3, -3, 1, -3]$$ ### Second Column of $$B$$: $$[-3, -1, -2, 0]$$ ### Compute $$C_1^2$$: $$C_1^2 = 3 \cdot (-3) + (-3) \cdot (-1) + 1 \cdot (-2) + (-3) \cdot 0$$ $$C_1^2 = -9 + 3 - 2 + 0 = -8.$$ ### Final Answer: $$C_1^2 = -8.$$ Would you like a detailed breakdown of another part or clarification? --- ### Follow-Up Questions: 1. How is matrix multiplication defined for non-square matrices? 2. What are the dimensions of the resulting matrix when $$A$$ and $$B$$ are multiplied? 3. How would the computation change if the matrices were larger? 4. Can the process be simplified for sparse matrices? 5. How do the elements of $$A$$ influence the rows of $$C$$? ### Tip: When performing matrix multiplication, always ensure the **number of columns in the first matrix matches the number of rows in the second matrix**.

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Math Problem Analysis

Mathematical Concepts

Matrix Multiplication
Linear Algebra

Formulas

C_ij = Σ(A_ik * B_kj), where k iterates over columns of A and rows of B

Theorems

Matrix Multiplication Rule

Suitable Grade Level

Undergraduate Mathematics or Advanced High School Algebra