#Linear Algebra: Matrix multiplication!

45 messages · Page 1 of 1 (latest)

dim knoll
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How would I calculate the coordinates x1, x2, x3, x4 for the vector x?

tepid pikeBOT
dim knoll
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I thought of this approach, but wouldn't know how to continue...

hazy olive
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Gaussian elimination

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Just use row operations to get to row echelon form

dim knoll
hazy olive
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Ah I didn’t see

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Hm

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You can just try to brute force it ig?

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With normal system of lin eq solving

dim knoll
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I wouldn’t know how to do that

molten torrent
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You can do gaussian elimination when you don't have square matrices

hazy olive
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Yeah

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You can

blazing moon
hazy olive
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No, you have some 0s

molten torrent
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So you should end up with at least a 1-dimensional solution space.

hazy olive
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Or that

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yeah

molten torrent
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Just depending on how many free variables you have leftover.

dim knoll
molten torrent
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So you have a 2-dimensional vector space.

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x_3 and x_4 can be anything you want

hazy olive
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Yeah ur solution space is in R^2

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🙏🙏🙏

dim knoll
molten torrent
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That's the solution.

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You'd write it as $\begin{bmatrix}2-2x_{3}-3x_{4}\1-3x_{3}-2x_{4}\x_{3}\x_{4}\end{bmatrix}$

supple coralBOT
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Riesz Rambutan Theorem

molten torrent
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Any values of $x_{3}$ or $x_{4}$ you pick would work.

supple coralBOT
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Riesz Rambutan Theorem

dim knoll
molten torrent
supple coralBOT
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Riesz Rambutan Theorem

dim knoll
molten torrent
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That's sort of what I did.

dim knoll
dim knoll
molten torrent
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Calculate $A\begin{bmatrix}x_{1}\x_{2}\x_{3}\x_{4}\end{bmatrix}$. It should be a length-3 vector. Then work out $A\begin{bmatrix}x_{1}\x_{2}\x_{3}\x_{4}\end{bmatrix}=\begin{bmatrix}0\0\0\end{bmatrix}$.

supple coralBOT
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Riesz Rambutan Theorem

dim knoll
molten torrent
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All of undergrad LA is basically matrix multiplication or row-reduction.

dim knoll
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What does undergrad LA mean?

molten torrent
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Undergrad linear algebra.