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Ok I have been struggling a lot with this problem and I hope some of you might be able to help me out.

Let's take this image:

http://img822.imageshack.us/img822/3828/capturelqe.png [Broken]

All these dots labeled x1 to x25 are temperature points. All the dots along the edges of the main square are starting temperature values (all the 5 dots of one side have the same temperature) (the dots don't look connected at the side of B and C but they are)

A = 40

B = 0

C = 10

D = 40

Every point's temperature is dependent on the directly neighboring point's temperature. So the average temperature of a point is:

x1= 1/4(40+40+x2+x6)

x9= 1/4(x4+x8+x10+x14)

So now they are asking us to solve for all the points with MATLAB. I do have experience with matlab but I have no clue how to set up this system of equations even on paper.

I'm supposed to use Ax = y where A is a 25x25 matrix and y is an element or R^25

First of all I don't understand why A is a 25x25 matrix. Shouldn't it be a 5x5 matrix?

Furthermore I am also not sure what A, x or y needs to contain in this case. Of course I know how to solve regular system of equations. I've been doing this for a year now but the 25x25 matrix is just completely throwing me off.

Help please? :)

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# Linear Algebra question (system of equations)

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