Matrix Simplification: A = HG(FHG)^{-1}FG | Step-by-Step Solution

  • Thread starter Thread starter JFonseka
  • Start date Start date
  • Tags Tags
    Matrix
AI Thread Summary
The discussion focuses on simplifying the matrix equation A = HG(FHG)^{-1}FG. The initial attempt correctly identifies that (FHG)^{-1} can be expressed as F^{-1}H^{-1}G^{-1}. The simplification process leads to the identity matrices I, which are ultimately eliminated, resulting in A = G. A participant initially questions the disappearance of the identity matrices but later realizes that multiplying by the identity matrix does not change the value of the matrix. The final answer confirmed in the discussion is A = G.
JFonseka
Messages
117
Reaction score
0

Homework Statement



Simplify

A = HG(FHG)^{-1}FG

Homework Equations



None

The Attempt at a Solution



Well (FHG)^-1 is really just F^-1 H^-1 G^-1
Therefore A = HGG^{-1}H^{-1}F^{-1}FG
GG^-1 = I
FF-1 = I

Therefore A = HIH^{-1}(IG)

The book now simplifies to HH^{-1}G

I understand all the steps and the ending step, but I don't get how they got rid of the two I's

I X I = I (Identity Matrix), so where did it disappear to?

The final answer is: A = G

Thanks
 
Physics news on Phys.org
Urgh, silly me, solved.

Identity matrix multiplied by another matrix just returns that matrix I forgot.

Silly problem. Sorry.
 
JFonseka said:
Well (FHG)^-1 is really just F^-1 H^-1 G^-1

Not really. (FHG)^-1 = (G^-1)*(H^-1)*(F^-1).
 
I picked up this problem from the Schaum's series book titled "College Mathematics" by Ayres/Schmidt. It is a solved problem in the book. But what surprised me was that the solution to this problem was given in one line without any explanation. I could, therefore, not understand how the given one-line solution was reached. The one-line solution in the book says: The equation is ##x \cos{\omega} +y \sin{\omega} - 5 = 0##, ##\omega## being the parameter. From my side, the only thing I could...
Back
Top