# matrix orthogonal

• May 9th 2008, 01:53 AM
deragon999
matrix orthogonal
This is probably easier than I think it looks but..im stumped...
Here goes

A is an n x n orthoganal matrix...show that a^t(transpose of a) is also orthoganal

• May 9th 2008, 02:30 AM
mr fantastic
Quote:

Originally Posted by deragon999
This is probably easier than I think it looks but..im stumped...
Here goes

A is an n x n orthoganal matrix...show that a^t(transpose of a) is also orthoganal

It follows from the definition! Read

Orthogonal matrix - Wikipedia, the free encyclopedia

to see what I mean ....
• May 9th 2008, 09:23 AM
Moo
Hello,

Quote:

Originally Posted by deragon999
This is probably easier than I think it looks but..im stumped...
Here goes

A is an n x n orthoganal matrix...show that a^t(transpose of a) is also orthoganal

A matrix A is orthogonal if $A^{-1}=A^t$
$(A^{-1})^t=(A^t)^t$
$\implies (A^t)^{-1}=(A^t)^t$
Hence $A^t$ is orthogonal...