## Quick Matrix Question

Looking over a proof of something, I was confused at this step:

We end up with: R$$^{T}$$ R = I (the identity matrix)
This must mean that R$$^{-1}$$ = R$$^{T}$$

This is confusing me because I know that A A$$^{-1}$$ = I , but in the R case the transpose is on the left side instead of the right, and it seems to me that it matters what order the matrices are multiplied.

 PhysOrg.com science news on PhysOrg.com >> 'Whodunnit' of Irish potato famine solved>> The mammoth's lament: Study shows how cosmic impact sparked devastating climate change>> Curiosity Mars rover drills second rock target
 Okay, start with $$AA^{-1}=I$$. Can you turn this into $$A^{-1}A=I$$?