Simplify the matrix product to the identity

In summary, we are given that G, H, and G+H are invertible matrices with the same dimensions. We need to prove that G(G^-1 + H^-1)H(G+H)^-1 = I. In our attempt, we expanded the multiplication and simplified it to 2GH^-1 + GH^-1GH^-1. We are now unsure of how to proceed.
  • #1
hellokitten
12
1

Homework Statement


IF G, H and G+H are invertible matrices and have the same dimensions
Prove that G(G^-1 + H^-1)H(G+H)^-1 = I

3. Attempt
G(G^-1 +H^-1)(G+H)H^-1 = G(G^-1G +G^-1H + H^-1G + H^-1H)H^-1
= (GG^-1GH^-1 +GG^-1HH^-1 +GH^-1GH^-1 +GH^-1HH^-1) = GH^-1+I +GH^-1GH^-1 +GH^-1
=2GH^-1+ GH^-1GH^-1

I am not sure where to go from here.
 
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  • #2
hellokitten said:

Homework Statement


IF G, H and G+H are invertible matrices and have the same dimensions
Prove that G(G^-1 + H^-1)H(G+H)^-1 = I

3. Attempt
G(G^-1 +H^-1)(G+H)H^-1 = G(G^-1G +G^-1H + H^-1G + H^-1H)H^-1
= (GG^-1GH^-1 +GG^-1HH^-1 +GH^-1GH^-1 +GH^-1HH^-1) = GH^-1+I +GH^-1GH^-1 +GH^-1
=2GH^-1+ GH^-1GH^-1

I am not sure where to go from here.

Try starting with multiplying out what I have highlighted in red, then multiply the blue into that and see what it looks like.
 
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  • #3
hellokitten said:

Homework Statement


IF G, H and G+H are invertible matrices and have the same dimensions
Prove that G(G^-1 + H^-1)H(G+H)^-1 = I

3. Attempt
G(G^-1 +H^-1)(G+H)H^-1

Where did that starting expression come from?
Just expand the multiplications from left to right. What is G(G-1+H-1)?
Multiply the result with H from the right . What do you get?

LCKurtz was faster... :D
 

FAQ: Simplify the matrix product to the identity

What is the matrix product?

The matrix product is a mathematical operation that involves multiplying two matrices together to create a new matrix. It is similar to multiplying two numbers, but instead of resulting in a single number, it results in a new matrix with different dimensions.

What does it mean to simplify the matrix product to the identity?

Simplifying the matrix product to the identity means to find the specific values of the matrices involved in the product so that the result is the identity matrix. The identity matrix is a special matrix that, when multiplied with any other matrix, results in the same matrix.

Why is it important to simplify the matrix product to the identity?

Simplifying the matrix product to the identity is important because it allows us to solve systems of equations, find inverse matrices, and perform other operations more easily. It also helps us understand the properties and behavior of matrices.

What are the steps involved in simplifying the matrix product to the identity?

The steps involved in simplifying the matrix product to the identity include identifying the matrices involved, determining their dimensions, checking if the product is possible, performing the multiplication, and solving for the specific values of the matrices to get the identity matrix.

Can all matrix products be simplified to the identity?

No, not all matrix products can be simplified to the identity. It depends on the specific values and dimensions of the matrices involved. Some matrix products may not have a solution, while others may result in a different matrix instead of the identity matrix.

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