AP EAMCET20224 Jul 2022Evening ShiftMathematicsMatricesActual
If A = 1 0 0 a - 1 0 b c 1 is such that A 2 = I , then
Options
- Ab = a c 2
- Bb = - a c 2
- Cb = a + c 2
- Db = a c
Correct answer
B. b = - a c 2
Step-by-step solution
Given: A = 1 0 0 a - 1 0 b c 1 And, A 2 = I ⇒ 1 0 0 a - 1 0 b c 1 1 0 0 a - 1 0 b c 1 = 1 0 0 0 1 0 0 0 1 ⇒ 1 0 0 0 1 0 2 b + a c 0 1 = 1 0 0 0 1 0 0 0 1 So, 2 b + a c = 0 ⇒ b = - a c 2