Math Is Fun Forum

samuel12

Member

Registered: 2010-07-17

Posts: 19

more linear algebra

Hi can anyone explain a method to solve this problem

let A,B be two matrices where

A=[1,0,-2;-3,1,1;2,0,-1]  (where ; seperates the rows of the matrix)
B=[2,3,0;1,-1,1;-1,6,4]

Use the matrix-column representation of the product to write each column of BA as a linear combination of the columns of B.

cheers guys

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: more linear algebra

Hi;

The actual symbolic form of matrix multiplication demonstrates that.

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

samuel12

Member

Registered: 2010-07-17

Posts: 19

Re: more linear algebra

Ok after a little thought power i managed to solve it....

From MATLAB B*A is:

Now we simply set up the equations

and solve each one for c1 c2 c3 by augmenting each system of equations and using rref or back substitution...

for the first equation:

will do.

for the second equation:

will do.

and lastly, for the third equation:

will do.

So we have written each column of BA as a linear combination of the columns of B.