Math Problem Statement

Invers matriks A = [[-2, 3], [-2, 4]] adalah ...

Solution

To find the inverse of the matrix A=[2324]A = \begin{bmatrix} -2 & 3 \\ -2 & 4 \end{bmatrix}, we follow these steps:

  1. Find the determinant of the matrix: det(A)=(2)(4)(2)(3)=8+6=2\text{det}(A) = (-2)(4) - (-2)(3) = -8 + 6 = -2

  2. Compute the adjugate matrix: Swap the diagonal elements and negate the off-diagonal elements: Adj(A)=[4322]\text{Adj}(A) = \begin{bmatrix} 4 & -3 \\ 2 & -2 \end{bmatrix}

  3. Divide the adjugate matrix by the determinant: A1=1det(A)Adj(A)A^{-1} = \frac{1}{\text{det}(A)} \cdot \text{Adj}(A) Substituting det(A)=2\text{det}(A) = -2:

    = \begin{bmatrix} -2 & \frac{3}{2} \\ -1 & 1 \end{bmatrix}$$

The correct inverse is: Option A: [23211]\boxed{\text{Option A: } \begin{bmatrix} -2 & \frac{3}{2} \\ -1 & 1 \end{bmatrix}}

Would you like more details on how the adjugate or determinant was calculated?


Related Questions:

  1. What is the determinant, and why is it important for inverses?
  2. Can all square matrices be inverted?
  3. What happens if the determinant is zero?
  4. How is the adjugate matrix derived systematically?
  5. How can this process be extended to larger matrices?

Tip:

For 2x2 matrices, the inverse formula is quick: swap diagonals, negate off-diagonals, and divide by the determinant.

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Math Problem Analysis

Mathematical Concepts

Linear Algebra
Matrix Inversion

Formulas

Determinant of 2x2 matrix: det(A) = ad - bc
Inverse of 2x2 matrix: A^(-1) = (1/det(A)) * adj(A)
Adjugate matrix: Swap diagonal elements and negate off-diagonal elements

Theorems

Matrix Inversion Theorem

Suitable Grade Level

Grades 10-12