JEE Main | 2014MatricesHard
Question
If A is an 3 × 3 non-singular matrix such that AA′ = A′A and B = A-1A′, then BB′ equals
Options
A.B-1
B.(B-1)′
C.I + B
D.I
Solution
BB′ = (A-1 .A′)(A(A-1)′)
= A-1 .A.A′.(A-1)1 {as AA′ = A′A}
= I(A-1A)′
= I.I = I2 = I
= A-1 .A.A′.(A-1)1 {as AA′ = A′A}
= I(A-1A)′
= I.I = I2 = I
Create a free account to view solution
View Solution FreeMore Matrices Questions
If D = diag (d1, d2,.....,dn), then Dn equals -...If a matrix A is such that 3A3 + 2A2 + 5A + I = 0, then A-1 is equal to-...Matrix is a -...If $X = \begin{bmatrix} x \\ y \\ z \end{bmatrix}$ is a solution of the system of equations$AX = B$, where adj $A = \beg...If A be a matrix such that inverse of 7A is the matrix , then A equals -...