Math Problem Statement

If A = [[-4, 4, 4], [-7, 1, 3], [5, -3, -1]] and B = [[1, -1, 1], [1, -2, -2], [2, 1, 3]], find A.B and solve the system of equations x - y + 3z = 4, x - 2y - 2z = 9, 2x + y + 3z = 1.

Solution

Let's solve the problem in two steps:

  1. Matrix Multiplication ABA \cdot B:
    Given matrices AA and BB, we need to compute the product ABA \cdot B.

    Matrix AA:

    -4 & 4 & 4 \\ -7 & 1 & 3 \\ 5 & -3 & -1 \end{bmatrix}$$ Matrix $$B$$: $$B = \begin{bmatrix} 1 & -1 & 1 \\ 1 & -2 & -2 \\ 2 & 1 & 3 \end{bmatrix}$$ The product $$A \cdot B$$ is computed as follows: $$(A \cdot B)_{ij} = \sum_{k=1}^3 A_{ik} \cdot B_{kj}$$
  2. Solving the system of linear equations: The system is:

    x - y + 3z &= 4 \\ x - 2y - 2z &= 9 \\ 2x + y + 3z &= 1 \end{aligned}$$ This system can be written as a matrix equation $$C \cdot \vec{x} = \vec{b}$$, where: $$C = \begin{bmatrix} 1 & -1 & 3 \\ 1 & -2 & -2 \\ 2 & 1 & 3 \end{bmatrix}, \quad \vec{x} = \begin{bmatrix} x \\ y \\ z \end{bmatrix}, \quad \vec{b} = \begin{bmatrix} 4 \\ 9 \\ 1 \end{bmatrix}$$ Solve for $$\vec{x}$$ using $$\vec{x} = C^{-1} \cdot \vec{b}$$.

Let me compute these step-by-step.import numpy as np

Define matrices A and B

A = np.array([[-4, 4, 4], [-7, 1, 3], [5, -3, -1]]) B = np.array([[1, -1, 1], [1, -2, -2], [2, 1, 3]])

Compute A * B

AB = np.dot(A, B)

Define the coefficient matrix C and vector b for the system of equations

C = np.array([[1, -1, 3], [1, -2, -2], [2, 1, 3]]) b = np.array([4, 9, 1])

Solve the system of equations C * x = b

solution = np.linalg.solve(C, b)

AB, solution(array([[8, 0, 0], [0, 8, 0], [0, 0, 8]]), array([ 2.55555556, -2.77777778, -0.44444444]))(array([[8, 0, 0], [0, 8, 0], [0, 0, 8]]), array([ 2.55555556, -2.77777778, -0.44444444]))successHere are the results:

  1. Matrix Multiplication ABA \cdot B: 8 & 0 & 0 \\ 0 & 8 & 0 \\ 0 & 0 & 8 \end{bmatrix}$$
  2. Solution to the system of equations: x=2.56,y=2.78,z=0.44x = 2.56, \quad y = -2.78, \quad z = -0.44 (Values are rounded to two decimal places.)

Would you like detailed steps for the matrix multiplication or solving the system of equations?

Here are 5 additional related questions for exploration:

  1. What is the determinant of matrix AA?
  2. Can the system of equations be solved using Gaussian elimination? If so, how?
  3. What are the eigenvalues and eigenvectors of ABA \cdot B?
  4. Is ABA \cdot B a diagonal matrix? Why?
  5. Can matrix BB be inverted, and if so, what is its inverse?

Tip: Understanding how to solve linear equations with matrix methods will help in working with systems of equations in applied contexts like engineering and physics!

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Math Problem Analysis

Mathematical Concepts

Matrix Multiplication
Linear Algebra
System of Equations

Formulas

Matrix multiplication formula: (A·B)ij = Σ(Aik * Bkj)
Solution of a linear system: x = C^-1 * b

Theorems

Inverse matrix theorem
Properties of matrix multiplication

Suitable Grade Level

Grades 11-12