Solving a Matrice Equation: AX=B

  • MHB
  • Thread starter Petrus
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In summary, the conversation discusses solving a matrix equation with given matrices A, X, and B. There is a question about whether there is a solution, but it is determined that there is one and it is given by X=A^{-1}B. A calculation is shown to prove this.
  • #1
Petrus
702
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Matrice equation

Hello MHB,
I am suposed to solve this matrice equation \(\displaystyle AX=B\)
\(\displaystyle A=
\left| {\begin{array}{cc} 1 & 2 & 1\\ 1 & 3 & 2\\ 1 & 6 & 6 \end{array} } \right|\)
\(\displaystyle X=
\left| {\begin{array}{cc} a & b \\ c & d \\ e & f \end{array} } \right|\)
\(\displaystyle B=
\left| {\begin{array}{cc} 1 & 10 \\ 2 & 40 \\ 3 & 60 \end{array} } \right|\)

Well I don't need to try do something I can se there will be no solution cause I will not be able to multiplication \(\displaystyle A^{-1}*B\) cause there is not same row in A as columne in B so there will be no solution? I am correct?

Regards,
\(\displaystyle |\pi\rangle\)
 
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  • #2
Re: Matrice equation

No problem with orders, they fit perfectly. Besides, $A$ is invertible so, $$AX=B\Leftrightarrow A^{-1}(AX)=A^{-1}B\Leftrightarrow (AA^{-1})X=A^{-1}B\Leftrightarrow IX=A^{-1}B\Leftrightarrow X=A^{-1}B$$ Now, $X=A^{-1}B=\ldots$
 
  • #3
Re: Matrice equation

Fernando Revilla said:
No problem with orders, they fit perfectly. Besides, $A$ is invertible so, $$AX=B\Leftrightarrow A^{-1}(AX)=A^{-1}B\Leftrightarrow (AA^{-1})X=A^{-1}B\Leftrightarrow IX=A^{-1}B\Leftrightarrow X=A^{-1}B$$ Now, $X=A^{-1}B=\ldots$
Hello Fernando Revilla,
Thanks, I see what I did misinterpret.

Regards,
\(\displaystyle |\pi\rangle\)
 

FAQ: Solving a Matrice Equation: AX=B

What is a matrix equation?

A matrix equation is a mathematical equation in which matrices are used to represent the variables and constants. It can be solved by manipulating the matrices using various operations.

What is the purpose of solving a matrix equation?

The purpose of solving a matrix equation is to find the values of the variables that satisfy the equation. This can help in solving various real-world problems, such as finding optimal solutions in engineering and economics.

What are the steps involved in solving a matrix equation?

The steps involved in solving a matrix equation include formulating the equation, reducing the matrices to row-echelon form, applying back substitution to solve for the variables, and verifying the solution by substituting it back into the original equation.

What are the different methods used to solve a matrix equation?

Some of the commonly used methods to solve a matrix equation are Gaussian elimination, Cramer's rule, inverse matrix method, and LU decomposition. The choice of method may depend on the size and complexity of the equation.

What are the possible outcomes of solving a matrix equation?

There are three possible outcomes of solving a matrix equation: a unique solution, no solution, or infinitely many solutions. The outcome depends on the coefficients and constants in the equation and can be determined by examining the row-echelon form of the augmented matrix.

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