What is A(2)x in the given system of equations?

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Homework Help Overview

The discussion revolves around a system of equations involving a matrix A(2) and a vector b(c). The original poster seeks to determine the value of the parameter c such that A(2)x equals b(c), where x is a vector of variables and b(c) is defined as (1, c, 1). The matrix A(2) is derived from a previous problem that involves a specific 3x3 matrix.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants question the definition and calculation of the matrix A(2), as it has not been explicitly provided. There is uncertainty about how to derive A(2) from the given 3x3 matrix and how the parameter b influences the system. The original poster expresses confusion about substituting values and the meaning of A(2)x.

Discussion Status

The discussion is ongoing, with participants seeking clarification on the relationship between the matrix A(2) and the previous problem. Some participants have attempted to summarize the information but acknowledge the lack of clarity regarding the calculation of A(2) and its implications for solving the problem.

Contextual Notes

There is a noted absence of information regarding how to compute A(2) from the previous example, which complicates the understanding of the problem. The original poster also mentions potential language barriers that may contribute to the confusion.

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Homework Statement


Decide c, so that A(2)X=b(c) where

x=(x,y,z) and b(c)=(1,c,1)
A(2) is calculated from the previous problem:

"Decide the value on the parameter b so that the following system has solutions

(2, 1,-1,b
1, 2, 2, 2b
1,-1,-3, b+1)


Homework Equations





The Attempt at a Solution


Alright, I solved the previous problem that is stated and I got the answer to be b=-1/2
but from that, what do I do? The real question is, what does A(2)x mean? I substitute b for 2?

/Magnus
 
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There seems to be some information missing. You mentioned a matrix A(2), but didn't show what it is.

You listed something else, namely
(2, 1,-1,b
1, 2, 2, 2b
1,-1,-3, b+1)
without explaining what it is.

What exactly is the problem you're trying to solve?
 
Mark44 said:
There seems to be some information missing. You mentioned a matrix A(2), but didn't show what it is.

You listed something else, namely
(2, 1,-1,b
1, 2, 2, 2b
1,-1,-3, b+1)
without explaining what it is.

What exactly is the problem you're trying to solve?


The matrix A(2) is calculated from that one.
"decide the number c so that A(2)x=b(c)
where:
x= (x,y,z) and b(c)=(1,c,1)

A(2) is calculated from the previous example."
The previous example is:
Determine the value on the parameter b so that the following system has solutions:
(2, 1,-1,b
1, 2, 2, 2b
1,-1,-3, b+1)
Where this represents a 3x3 matrix. Any ideas?
 
By "that one" I assume you mean this 3 x 3 matrix (shown by rows):
{(2 1 -1), (1 2 2), (1 -1 -3)}

The matrix A(2) is calculated from that one.
and
A(2) is calculated from the previous example.

So, to summarize, A(2) is not shown and no description on how to get it is shown, and you don't know what it means.

Not much to go on...
 
Mark44 said:
By "that one" I assume you mean this 3 x 3 matrix (shown by rows):
{(2 1 -1), (1 2 2), (1 -1 -3)}


and


So, to summarize, A(2) is not shown and no description on how to get it is shown, and you don't know what it means.

Not much to go on...
I'm sorry, it's probably my bad english that confuses you. A(2) is calculated from that 3x3 matrix yes, and I have no idea how to get it either. Do you have any idea?
 
A 3x3 augmented matrix where the bs are the parameters. Just to clarify.
 
No ideas?
 
"Calculated from it" HOW? "Calculating" it from the previous problem doesn't make sense because the only question in that problem is determing b which is only in the right hand side of the equation, not the coefficient matrix. Do you mean that it is the matrix
[tex]\left[\begin{array}{ccc} 2 & 1 & -1\\ 1 & 2 & 2 \\ 1 & -1 & -3\end{array}\right][/tex]?

If so then the problem is to solve
[tex]\left[\begin{array}{ccc} 2 & 1 & -1\\ 1 & 2 & 2 \\ 1 & -1 & -3\end{array}\right]\left[\begin{array}{c} x \\ y \\ z\end{array}\right]= \left[\begin{array}{ccc} 1 \\ c \\ 1\end{array}\right][/tex]
 
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