JEE Main202225 Jun 2022Evening ShiftMathematicsMatricesActual
Let A = 2 - 2 1 - 1 and B = - 1 2 - 1 2 . Then the number of elements in the set n , m : n , m ∈ 1 , 2 , … … . 10 and n A n + m B m = I is _____.
Correct answer
0
Step-by-step solution
Given, A = 2 - 2 1 - 1 So, A 2 = 2 - 2 1 - 1 2 - 2 1 - 1 = 2 - 2 1 - 1 = A Also, B = - 1 2 - 1 2 B 2 = - 1 2 - 1 2 - 1 2 - 1 2 = - 1 2 - 1 2 = B So, A + B = 2 - 2 1 - 1 + - 1 2 - 1 2 = 1 0 0 1 = I Therefore the equation n A n + m B m = I is true for n = 1   &   m = 1 so, only one set is possible.