Matrices — Easy JEE math MCQ
If A = [[2, 3], [1, 2]], then A⁻¹ is:
- A. [[2, -3], [-1, 2]]
- B. [[-2, 3], [1, -2]]
- C. [[2, 3], [1, 2]]
- D. [[1/2, -3/2], [-1/2, 1]]
Solution
For a 2×2 matrix [[a,b],[c,d]], A⁻¹ = (1/det A) × [[d,-b],[-c,a]]. Here det A = 4-3 = 1. So A⁻¹ = [[2,-3],[-1,2]].