By signing in you confirm you are 18 or older, or have your parent’s or guardian’s consent.

NDA 2 2025 Maths, question 10

Topic: Matrices and determinants

Q10

What is the value of the determinant of the inverse of the matrix

[−4−522]\begin{bmatrix} -4 & -5 \\ 2 & 2 \end{bmatrix}?

  1. (a) 12\frac{1}{2}Correct answer
  2. (b) 11
  3. (c) 22
  4. (d) 44

Solution.

Answer: (a) 12\frac{1}{2}

  1. The determinant of the given matrix is (−4)×2−(−5)×2=2.
  2. For an invertible matrix, det(A⁻¹)=1/det(A), giving 1/2.