#Linear Algebra: Matrix multiplication!
45 messages · Page 1 of 1 (latest)
I thought of this approach, but wouldn't know how to continue...
Yes, but this matrix seems a bit different as it is not a square matrix (m = n)
Ah I didn’t see
Hm
You can just try to brute force it ig?
With normal system of lin eq solving
I wouldn’t know how to do that
You can do gaussian elimination when you don't have square matrices
Isn't that impossible? You'd have a system of 3 equations with 4 variables...
No, you have some 0s
So you should end up with at least a 1-dimensional solution space.
Just depending on how many free variables you have leftover.
I could solve it to this point
What would be the next step for this?
That's the solution.
You'd write it as $\begin{bmatrix}2-2x_{3}-3x_{4}\1-3x_{3}-2x_{4}\x_{3}\x_{4}\end{bmatrix}$
Riesz Rambutan Theorem
Any values of $x_{3}$ or $x_{4}$ you pick would work.
Riesz Rambutan Theorem
Where does the first number come from first row: 2 and second row: 1?
What this is saying is that $x_{1}+2x_{3}+3x_{4}=2$ and $-x_{2}-3x_{3}-2x_{4}=-1$.
Riesz Rambutan Theorem
Okay, I see
I'd also do the second part of the task
That's sort of what I did.
Now I get the point. Thanks for clarifying! 👍
How would I go for this?
Calculate $A\begin{bmatrix}x_{1}\x_{2}\x_{3}\x_{4}\end{bmatrix}$. It should be a length-3 vector. Then work out $A\begin{bmatrix}x_{1}\x_{2}\x_{3}\x_{4}\end{bmatrix}=\begin{bmatrix}0\0\0\end{bmatrix}$.
Riesz Rambutan Theorem
So is it basically the same as the previous task?
All of undergrad LA is basically matrix multiplication or row-reduction.
What does undergrad LA mean?
Undergrad linear algebra.