A square matrix A is called skew-symmetric if A^T= A. Prove that if A is a skew-symmetric n x nmatrix and n is odd, then A is not inveritible.

what if n is even ?

Please help, I have no idea what is talking about.

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- Mar 20th 2011, 07:32 AMmove123A square matrix A is called skew-symmetric
A square matrix A is called skew-symmetric if A^T= A. Prove that if A is a skew-symmetric n x nmatrix and n is odd, then A is not inveritible.

what if n is even ?

Please help, I have no idea what is talking about. - Mar 20th 2011, 08:18 AMTheEmptySet
Hello move123,

First your definition is incorrect. A matrix is skew symmetric if

First we know that a matrix and its transpose have the same determinant. This gives

Since the determinant function is multi-linear when we factor an number out of an n by n matrix it will have the power n e.g

when A is an n by n matrix.

using this on the first equation gives

This gives

Now what can we say about the determinant when n is odd? - Mar 20th 2011, 08:53 AMFernandoRevilla
- Mar 20th 2011, 09:50 AMmove123
- Mar 20th 2011, 11:08 AMFernandoRevilla