Answer: 4A - I.
- A 4A - I
- B 4A + I
- C A + 4I
- D I - 4A
Correct answer: A. 4A - I
Explanation: Cayley-Hamilton theorem: every matrix satisfies its own characteristic equation. So A² - 4A + I = 0, which rearranges to A² = 4A - I. Answer: A² = 4A - I.
Concept context
Evaluation of determinants, cofactors, adjoint, inverse of matrix, Cramer's rule and area applications. Always in board and JEE.