Commerce (English Medium) कक्षा १२ - CBSE Question Bank Solutions for Mathematics

If \[A = \begin{bmatrix}a & b \\ c & d\end{bmatrix}, B = \begin{bmatrix}1 & 0 \\ 0 & 1\end{bmatrix}\] , find adj (AB).

If \[A = \begin{bmatrix}3 & 1 \\ 2 & - 3\end{bmatrix}\], then find |adj A|.

If \[A = \begin{bmatrix}2 & 3 \\ 5 & - 2\end{bmatrix}\] , write  \[A^{- 1}\] in terms of A.

If A is an invertible matrix, then which of the following is not true ?

If A is an invertible matrix of order 3, then which of the following is not true ?

If \[A = \begin{bmatrix}3 & 4 \\ 2 & 4\end{bmatrix}, B = \begin{bmatrix}- 2 & - 2 \\ 0 & - 1\end{bmatrix},\text{ then }\left( A + B \right)^{- 1} =\]

If \[S = \begin{bmatrix}a & b \\ c & d\end{bmatrix}\], then adj A is ____________ .

If A is a singular matrix, then adj A is ______.

If A, B are two n × n non-singular matrices, then __________ .

If \[A = \begin{bmatrix}a & 0 & 0 \\ 0 & a & 0 \\ 0 & 0 & a\end{bmatrix}\] , then the value of |adj A| is _____________ .

If \[A = \begin{bmatrix}1 & 2 & - 1 \\ - 1 & 1 & 2 \\ 2 & - 1 & 1\end{bmatrix}\] , then ded (adj (adj A)) is __________ .

If B is a non-singular matrix and A is a square matrix, then det (B⁻¹ AB) is equal to ___________ .

For any 2 × 2 matrix, if \[A \left( adj A \right) = \begin{bmatrix}10 & 0 \\ 0 & 10\end{bmatrix}\] , then |A| is equal to ______ .

If A⁵ = O such that \[A^n \neq I\text{ for }1 \leq n \leq 4,\text{ then }\left( I - A \right)^{- 1}\] equals ________ .

If A satisfies the equation \[x^3 - 5 x^2 + 4x + \lambda = 0\] then A^-1 exists if _____________ .

If for the matrix A, A³ = I, then A⁻¹ = _____________ .

For non-singular square matrix A, B and C of the same order \[\left( A B^{- 1} C \right) =\] ______________ .

The matrix \[\begin{bmatrix}5 & 10 & 3 \\ - 2 & - 4 & 6 \\ - 1 & - 2 & b\end{bmatrix}\] is a singular matrix, if the value of b is _____________ .

If d is the determinant of a square matrix A of order n, then the determinant of its adjoint is _____________ .

If \[A^2 - A + I = 0\], then the inverse of A is __________ .