0
$\begingroup$

enter image description here

1.

how can find vaiable $y_1,y_2,b_1,b_2$?

How the first matrix divided into smalle matrix$(4*x)$.

The second matrix is then multiplied.

So that the value of variable obtained.

2.

how can do this with matlab?

3.

What is the name of this action?

$\endgroup$
1
$\begingroup$

I don't know what you mean by $4*x \mid x > 0$, but you can divide the matrix into blocks as $$\left[\begin{array}{@{}cc|cc@{}}1 & 2 & 3 & 4 \\ 5 & 6 & 7 & 8 \\ \hline 9 & 10 & 11 & 12 \\ 1 & 4 & 3 & 1\end{array}\right]\begin{bmatrix}y_1 \\ y_2 \\ 3 \\ 4\end{bmatrix} = \begin{bmatrix}100 \\ 200 \\ b_1 \\ b_2\end{bmatrix}$$ so that you get $$\begin{array}{ccccc} \begin{bmatrix}1 & 2 \\ 5 & 6\end{bmatrix}\begin{bmatrix}y_1 \\ y_2\end{bmatrix} &+& \begin{bmatrix}3 & 4 \\ 7 & 8\end{bmatrix}\begin{bmatrix}3 \\ 4\end{bmatrix} &=& \begin{bmatrix}100 \\ 200\end{bmatrix} \\ \begin{bmatrix}9 & 10 \\ 1 & 4\end{bmatrix}\begin{bmatrix}y_1 \\ y_2\end{bmatrix} &+& \begin{bmatrix}11 & 12 \\ 3 & 1\end{bmatrix}\begin{bmatrix}3 \\ 4\end{bmatrix} &=& \begin{bmatrix}b_1 \\ b_2\end{bmatrix} \end{array}$$ which you can then rearrange to bring all the unknowns to the left-hand side and solve the system.

$\endgroup$
1
  • $\begingroup$ how can do this to matlab $\endgroup$ – Stack Overflow Apr 20 '12 at 9:43
0
$\begingroup$

To find values $y_1,y_2,b_1,b_2$ you should solve following system of four equations in four unknowns :

$$\begin{cases} y_1+y_2+9+16=100 \\ 5y_1+6y_2+21+32=200 \\ 9y_1+10y_2+33+48=b_1 \\ y_1+4y_2+9+4=b_2 \end{cases}$$

$\endgroup$
4
  • $\begingroup$ How did you get this equation?how can do this in matlab $\endgroup$ – Stack Overflow Apr 20 '12 at 9:43
  • $\begingroup$ @StackOverflow en.wikipedia.org/wiki/… $\endgroup$ – Peđa Terzić Apr 20 '12 at 9:46
  • $\begingroup$ how can do this in matlab $\endgroup$ – Stack Overflow Apr 20 '12 at 9:55
  • $\begingroup$ @StackOverflow I don't know $\endgroup$ – Peđa Terzić Apr 20 '12 at 9:57
0
$\begingroup$

[1 2 3 4] [$y_1$ $y_2$ 3 4]$^t$ =100 & [5 6 7 8] [$y_1$ $y_2$ 3 4]$^t$ =200

then $y_1=-39$ & $y_2=57 $

also [9 10 11 12] [-39 57 3 4]$^t$=[100 200 $b_1$ $b_2$] & [1 4 3 1] [-39 57 3 4]$^t$=[100 200 $b_1$ $b_2$]

then $b_1=300$ $b_2=202$

I computed it with matlab. enter image description here

$\endgroup$
1
  • $\begingroup$ this is right but if matrix have different value then..., for exmple i know that only first matrix have 4*4 dimension and second matrix in row[0]col[1]=y1 and row[2]col[1]=y2 and i does not know value of other only i know in other row and col have some number. in this answer you performe compute with static number 100 ,200 or other but i want work with place of number. $\endgroup$ – Stack Overflow Apr 20 '12 at 21:28

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.