The inverse of a 2x2 matrix [[a,b],[c,d]] is (when det ≠ 0):
A[[d,-b],[-c,a]]
B[[d,-b],[-c,a]] / det
C[[a,-b],[-c,d]]
D[[1/a,1/b],[1/c,1/d]]
Answer & Solution
Correct answer: B. [[d,-b],[-c,a]] / det
A⁻¹ = (1/det A) × [[d,-b],[-c,a]] for 2×2 matrix. Swap diagonals, negate off-diagonals, divide by determinant.
Related questions
If A is a 3×3 matrix with det(A) = 5, then det(2A) isDeterminant of a 2×2 matrix [[a,b],[c,d]] equalsIf A is invertible, then A × A⁻¹ equalsA matrix with the same number of rows and columns is calledIf A is invertible 2 × 2 and A² = I then A isDeterminant of a triangular matrix equalsA square matrix A is called symmetric ifIf A and B are square matrices of same order, in general