Simple Matrices proof using Mathematica help

In summary, the conversation is about a proof using Mathematica help. The goal is to prove that (AB)-1 = B-1 A-1 and its transpose using arbitrary 3x3 matrices A and B. The speaker was able to prove the transpose case by using the Transpose function and checking that it outputs "True". However, when they tried to use the Inverse function, they encountered an issue with the rounding off, causing the output to be "false". They suggest checking the syntax and making sure to use an asterisk between the two inverses.
  • #1
JJHK
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Simple Matrices proof using Mathematica help!

Homework Statement



Hey guys, I'm trying to prove that

(AB)-1 = B-1 A-1
and also the one that looks the same but is with transpose of the matrices

making A and B arbitrary 3x3 matrices. I made

A = {{a_1,a_2,a_3}...}
B = {{b_1,b_2,b_3}...}

and I was able to prove the Transpose one by typing "Transpose[A B] == Transpose * Transpose[A] " and it spit out the word "True"

However, when I write "Inverse[A B] == Inverse Inverse[A] ", it does not spit out the word true, rather it spits back out the matrices expanded. Does anyone know how to tweak it so that it'll spit out either the words true or false? Thanks


Homework Equations





The Attempt at a Solution

 
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  • #2


making A and B arbitrary 3x3 matrices.
... and checking that the inverse exists?
when I write "Inverse[A B] == Inverse Inverse[A] ", it does not spit out the word true
check syntax - did you write the above or did you write:

Inverse[A B] == Inverse*Inverse[A]

(I can't remember if it matters)

I find that the inverse function does some rounding off, and the rounding is different if I do inverse[A*B] and when I do inverse[A]*inverse, so whenever I do Inverse[A*B] == Inverse*Inverse[A] it returns "false".
 
Last edited:

Related to Simple Matrices proof using Mathematica help

1. What is a matrix and how is it used in mathematics?

A matrix is a rectangular array of numbers or symbols arranged in rows and columns. It is used in mathematics to represent and manipulate linear equations, transformations, and other mathematical operations.

2. How can Mathematica help with proofs involving matrices?

Mathematica is a powerful software that can perform symbolic calculations, including matrix operations. This can help with simplifying and verifying matrix equations and proofs.

3. Can Mathematica be used to solve systems of linear equations involving matrices?

Yes, Mathematica has built-in functions such as LinearSolve and Solve that can solve systems of linear equations involving matrices.

4. Is Mathematica compatible with other programming languages for matrix operations?

Yes, Mathematica has an extensive set of programming language interfaces, including Java, C, and Python, which can be used for matrix operations and other mathematical tasks.

5. Can Mathematica handle large matrices and perform computations efficiently?

Yes, Mathematica is designed to handle large matrices and perform computations efficiently. It also has parallel computing capabilities that can speed up calculations for even larger matrices.

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