Let A be ann xx n matrix and let B = A + A^T and C = A − A^T (a) Show that B is symmetric and C is skew symmetric. (b) Show that every n × n matrix can be represented as a sum of a symmetric matrix and a skew-symmetric matrix.

Josalynn

Josalynn

Answered question

2021-02-08

Let A be a nxxn matrix and let
B=A+ATandC=AAT
(a) Show that B is symmetric and C is skew symmetric.
(b) Show that every n × n matrix can be represented as a sum of a symmetric matrix and a skew-symmetric matrix.

Answer & Explanation

Nicole Conner

Nicole Conner

Skilled2021-02-09Added 97 answers

as we know that a matrix E is said to be symmetric if ET=E and skew symmetric if ET=E. 
as B=A+AT therefore, 
=BT=(A+AT)T 
=AT+(AT)T 
=AT+A(As(AT)T=A) 
=B 
as BT=B therefore, B is symmetric matrix. 
hence proved. 
As C=A−AT 
therefore, CT=(AAT)T 
=AT(AT)T 
=ATA 
=(AAT) 
=−C 
as CT=C therefore, C is skew symmetric matrix. Hence proved. 
Now we have to show that every nxxn matrix can be expressed as the sum of the symmetric and skew symmetric matrix. Let A be nxxn matrix. therefore, 
A=1/2(2A) 
=1/2(A+A) 
=1/2(A+AT+AAT) 
=1/2(B+C) 
where B=A+AT and B is a symmetric matrix and C=AAT and C is a skew symmetric matrix. 
herefore, 
A=1/2(B+C) 
=1/2(symmetric matrix +skew symmetric matrix) 
therefore, it has been showed that any matrix A of order nxxn can be expressed as the sum of symmetric and skew symmetric matrix.

Do you have a similar question?

Recalculate according to your conditions!

Ask your question.
Get an expert answer.

Let our experts help you. Answer in as fast as 15 minutes.

Didn't find what you were looking for?