Linear Algerbra. Inverses and Algerbraic Properties of Matrices

Join the discussion
Registration is free. Start your own thread to ask a follow-up.
2 replies · 2K views
stumpoman
Messages
10
Reaction score
1

Homework Statement


Assuming that all matrices, A, B, C, and D, are n x n and invertible, solve for D.

[itex]C^{T}B^{-1}A^{2}BAC^{-1}DA^{-2}B^{T}C^{-2}=C^{T}[/itex]

Homework Equations



[itex]C^{T}B^{-1}A^{2}BAC^{-1}DA^{-2}B^{T}C^{-2}=C^{T}[/itex]

The Attempt at a Solution



I must have missed something in the reading of this section. All I can think of is

[itex]B^{-1}A^{2}BAC^{-1}DA^{-2}B^{T}C^{-2}=I[/itex]

but I don't know where to go from there or if it is even the right way to start.
 
Physics news on Phys.org
stumpoman said:

Homework Statement


Assuming that all matrices, A, B, C, and D, are n x n and invertible, solve for D.

[itex]C^{T}B^{-1}A^{2}BAC^{-1}DA^{-2}B^{T}C^{-2}=C^{T}[/itex]
Just "undo" every thing that is done to D, one step at a time. For example if you multiply both sides, on the left, by [itex](C^T)^{-1}[/itex] you get [itex]B^{-1}A^{-2}BAC^{-1}DA^{-2}B^TC^{-2}= (C^T)^{-1}C^T= I[/itex]
Then multiply on the left by [itex]B[/itex], then on the right by [itex]C^2[/itex], or do both together to get [itex]A^{=2}BAC^{-1}DA^{-2}B^T= BC^2[/itex].
Continue to "unpeel" D.

Homework Equations



[itex]C^{T}B^{-1}A^{2}BAC^{-1}DA^{-2}B^{T}C^{-2}=C^{T}[/itex]

The Attempt at a Solution



I must have missed something in the reading of this section. All I can think of is

[itex]B^{-1}A^{2}BAC^{-1}DA^{-2}B^{T}C^{-2}=I[/itex]

but I don't know where to go from there or if it is even the right way to start.
Yes, that was the first step as I showed. Continue in the same way.