4x5 Matrix solution C=B/A receiving four solutions

I have inputted this matrix:
A = [1 8 9 2
2 7 8 3
3 5 7 4
4 1 6 5];
or
A = [1 8 9 2;2 7 8 3;3 5 7 4;4 1 6 5];
with:
B = [11;12;13;14];
C = B/A
error code:
??? 4x5 Matrix | Error: Missing MATLAB operator.

Answers (3)

The error message is certainly misleading. The problem is that if A is 4-by-4 and B is 4-by-1, the expression C = B/A is invalid. You are asking that matrix C satisfy the equation
C*A = B
but whatever C is, C*A must have four columns and yet B has only one column, so it is an impossible request.
Philosophaie
Philosophaie on 24 Jun 2013
Edited: Philosophaie on 24 Jun 2013
I am having a syntax error in the 4x4 array "A".
What am I entering wrong?

2 Comments

My version of matlab doesn't complain, but yours might object to what appears in this text to be a blank line between the first line and the rest of the A matrix input. Or perhaps it wants semicolons after each row. I still don't understand that error message. It is as though you had a fifth number entered in the first line.
My comment about the error in B/A still holds.
Yes it is X = A\B for A*X = B not B/A.
I want to make an m-file of this process.
This is probably why it was not working.

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A = [= [1.1 0 2.1 -3.5 6;0 1.1 -6.6 2.8 3.4;2.1 0.1 0.3 -0.4 1.3;-1.4 5.1 0 1.1 0]

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Asked:

on 24 Jun 2013

Answered:

on 28 Jun 2022

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