Tamilnadu +2 maths Important one mark question

                                 

                              Application of matrices and determinants

1.   If A is a matrix of order 3,then det (kA)

 (1) K³det(A)            (2) k²det(A)       (3) k det(A)       (4) det(A) 

2.   If I is a unit matrix of order n,where  k≠0 is a constant, then adj(kI)=

   (1)  Kⁿ (adj I)           (2)  k (adj I)       (3)  k² (adj (I))   (4) k^n-1 (adj I) 

  3.If the equation  -2x+y+z = l; x-2y+z = m; x+y-2z = n such that l + m + n = 0 , then the system  has

(1) A non-zero unique solution                  (2) trivial solution

( 3)  Infinitely many solution                    (4) no solution

  4.   If A and B are any two matrices such that AB=0 and A is non-singular, then

(1)B=0   (2)B is singular   (3)B is non singular     (4) B=A

5. If A is a square matrix of order 3, then det(kA)

(1) k³ det(A)  (2) k² det(A)      (3)  k det(A)      (4) det(A)

6.  Cramer's rule is applicable, when

(1) ∆ = 0                (2)  ∆ ≠ 0           (3)  ∆=1             (4)  ∆ ≠ 1

7. (A^T)^-1 is equal to

(1)  A^-1           (2)  A^T       (3)  A                (4)  (A^-1)^T