Cofactor Matrix Calculator (2×2)

Math

The Cofactor Matrix Calculator finds the matrix of cofactors of a 2×2 matrix, the first step toward the adjugate and inverse. Enter the four matrix entries.

Formula

For [[a,b],[c,d]] the cofactor matrix is [[d, −c], [−b, a]]
  • Each cofactor is the signed minor of the corresponding entry.
  • Transposing the cofactor matrix gives the adjugate, used to find the inverse.

[[4,1],[2,3]]

Inputs
  • a₁₁: 4
  • a₁₂: 1
  • a₂₁: 2
  • a₂₂: 3

Cofactor matrix = [[3, −2], [−1, 4]].

Frequently asked questions

What is a cofactor matrix?
It is the matrix of signed minors of each entry. For a 2×2 matrix [[a,b],[c,d]] it is [[d,−c],[−b,a]].