Math Problem Statement

how to calculate inverse of marix 3*3

Solution

To find the inverse of a 3x3 matrix, you can use the following steps, provided the matrix is invertible (i.e., its determinant is non-zero):

  1. Find the Determinant: Calculate the determinant det(A)\text{det}(A) of the 3x3 matrix AA. For a matrix A=(abcdefghi)A = \begin{pmatrix} a & b & c \\ d & e & f \\ g & h & i \end{pmatrix} the determinant is calculated as: det(A)=a(eifh)b(difg)+c(dheg)\text{det}(A) = a(ei - fh) - b(di - fg) + c(dh - eg)

  2. Calculate the Matrix of Minors: For each element in the matrix, calculate the determinant of the 2x2 submatrix that remains after removing the row and column of that element. This will give you a new 3x3 matrix, known as the matrix of minors.

  3. Form the Cofactor Matrix: Apply a checkerboard pattern of signs (+, -, + in the first row, etc.) to the matrix of minors to create the cofactor matrix.

  4. Transpose the Cofactor Matrix: This gives the adjugate (or adjoint) matrix.

  5. Divide by the Determinant: Finally, multiply each element in the adjugate matrix by ( \frac{1}{\text{

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Math Problem Analysis

Mathematical Concepts

Linear Algebra
Matrix Inversion
Determinants

Formulas

det(A) = a(ei - fh) - b(di - fg) + c(dh - eg)
Inverse of A = adj(A) / det(A)

Theorems

Cofactor expansion
Adjugate matrix

Suitable Grade Level

Grades 11-12