# Linear Algebra - Linear Algebra

11:

Eigen values of a real symmetric matrix are always

 A. positive B. real and imaginary C. negative D. real Answer Report Discuss Option: D Explanation : Click on Discuss to view users comments. Write your comments here:
12:

If AT = A-1, where A is a real matrix, then A is

 A. normal B. symmetric C. Hermitian D. orthogonal Answer Report Discuss Option: D Explanation : Click on Discuss to view users comments. Write your comments here:
13:

If A and B are non-zero square matrices, then AB = 0 implies

 A. A and B are orthogonal B. A and B are singular C. B is singular D. A is singular Answer Report Discuss Option: A Explanation : Click on Discuss to view users comments. MABUD ALI SARKAR said: (1:39pm on Thursday 10th December 2015) SINCE PRODUCT OF TWO NON-ZERO VECTORS IMPLIES THEY ARE ORTHOGONAL TO EACH OTHER. SO A and B ARE ORTHOGONAL Write your comments here:
14:

If A and B be real symmetric matrices of sizen n x n, then

 A. AAT = 1 B. A = A-1 C. AB = BA D. (AB)T = BA Answer Report Discuss Option: D Explanation : Click on Discuss to view users comments. MABUD ALI SARKAR said: (1:42pm on Thursday 10th December 2015) (AB)^T=(B^T)(A^T) =BA Zakir ali said: (8:30pm on Sunday 30th April 2017) Please tell me about different type of matrices with example Write your comments here:
15:

If, A, B, C are square matrices of the same order, then (ABC)-1 is equal to

 A. C-1A-1B-1 B. C-1 B-1 A-1 C. A-1 B-1C-1 D. A-1 C-1 B-1 Answer Report Discuss Option: B Explanation : Click on Discuss to view users comments. Write your comments here: