# Math Help - matrix orthogonal

1. ## 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

2. 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 ....

3. Hello,

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...