Solving system of equations for matrix?

AI Thread Summary
To solve the system of equations represented by the matrix Bx = 0, where B is a 3x2 matrix, the correct approach involves setting up the augmented matrix and reducing it to row echelon form. The user correctly sets up the augmented matrix but questions whether the solution x = (0, 0) is valid. The discussion clarifies that x = (0, 0) is indeed the only solution to the homogeneous equation Bx = 0, confirming that it is not incorrect. The confusion arises from misunderstanding the implications of the zero solution in the context of the system. The key takeaway is that the trivial solution is valid and expected in such systems.
mneox
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Homework Statement



Solve the system of equations for Bx = 0.

Where B is the following matrix:
[ 5 -1 ]
[ 2 2 ]
[ 1 4 ]

and the x is some vector I am assuming.. is it:
[ x1 ]
[ x2 ]

Homework Equations



The Attempt at a Solution



So what I figured was that I should do this:

[ 5 -1 | 0 ]
[ 2 2 | 0 ]
[ 1 4 | 0 ]

Is this correct? Then if I get it to rref

[ 1 0 | 0 ]
[ 0 1 | 0 ]
[ 0 0 | 0 ]

What do I do now? Is x1 = 0 and x2 = 0?

That seems like it's incorrect so I was wondering if someone can check over for me and offer any help? Thank you! :)
 
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Why do you think it's incorrect? You can check your work, you know. What do you get when you multiply
\left[\begin{array}{c c}5&amp;-1\\2&amp;2\\1&amp;4\end{array}\right]<br /> \left[\begin{array}{c}0\\0\end{array}\right]
What should you get?
 
Last edited:
Mark44 said:
Why do you think it's incorrect? You can check your work, you know. What do you get when you multiply
\left[\begin{array}{c c}5&amp;-1\\2&amp;2\\1&amp;4\end{array}\right]<br /> \left[\begin{array}{c}0\\0\end{array}\right]
What should you get?

Won't that give me a zero matrix? How would that help solve the system??
Sorry if I'm asking such stupid questions but it's been a long week..
 
The problem was to find an x such that Bx= 0. You have found that x= (0, 0) is the only such x. What is wrong with that?
 
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...

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