Math Problem Statement

Given M in Problems 39–48, find M^(-1) and show that M^(-1)M = I.

Solution

This problem requires finding the inverse M1M^{-1} for each given matrix MM in problems 39 through 44. After finding the inverse, we also need to verify that M1M=IM^{-1} M = I, where II is the identity matrix.

Let’s go through the steps to calculate the inverse of a 2x2 matrix. For a matrix

M=[abcd]M = \begin{bmatrix} a & b \\ c & d \end{bmatrix}

the inverse M1M^{-1} exists if the determinant det(M)=adbc0\det(M) = ad - bc \neq 0. The inverse, if it exists, is given by:

M1=1adbc[dbca]M^{-1} = \frac{1}{ad - bc} \begin{bmatrix} d & -b \\ -c & a \end{bmatrix}

I’ll start by calculating M1M^{-1} for each matrix and then verify that M1M=IM^{-1}M = I.

Let's solve each problem:


Problem 39

M=[1031]M = \begin{bmatrix} -1 & 0 \\ -3 & 1 \end{bmatrix}

  1. Determinant: det(M)=(1)(1)(0)(3)=1\det(M) = (-1)(1) - (0)(-3) = -1

  2. Inverse:

    M1=11[1031]=[1031]M^{-1} = \frac{1}{-1} \begin{bmatrix} 1 & 0 \\ 3 & -1 \end{bmatrix} = \begin{bmatrix} -1 & 0 \\ -3 & 1 \end{bmatrix}

  3. Verification: Compute M1MM^{-1}M to check if it equals the identity matrix.


Would you like me to continue with each matrix individually, or do you need help with a specific matrix from this set?

Also, here are some additional questions to expand your understanding:

  1. How do you find the determinant of a 3x3 matrix?
  2. What does it mean if the determinant of a matrix is zero?
  3. Can every square matrix be inverted? Why or why not?
  4. How can matrix inverses be used to solve systems of linear equations?
  5. What are some real-world applications of matrix inverses?

Tip: If you're having trouble with determinants, start by practicing with 2x2 matrices to build a strong foundation before moving to larger matrices.

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Math Problem Analysis

Mathematical Concepts

Matrix Inversion
Matrix Multiplication
Determinants

Formulas

M = [[a, b], [c, d]]
det(M) = ad - bc
M^(-1) = (1/det(M)) * [[d, -b], [-c, a]]

Theorems

Inverse of a 2x2 matrix
Properties of the Identity Matrix

Suitable Grade Level

Grades 10-12