MATLAB: Solving matrices in form of (A + Bx = C)

Question

% How do I write to solve for y?
A = [1 2; 3 4];
B = [0 0; 1 1];
y = [x1; x2];
C = [1; 0];
% y should be a 2x1, but I'm getting a 2x2.

Answer 1

As per my understanding of your code, in the equation A + Bx = C:

Matrix A is of size 2 * 2

Matrix B is of size 2 * 2

Matric C is of size 2 * 1

So when you are trying to perform the operations because of size mismatch of A, C & B*y your answer is evaluated to be a 2*2 matrix.

You can check the following code snippet for a better understanding of this:

A = [1 2; 3 4]; 
B = [0 0; 1 1]; 
C = [1; 0]; 
 
y = (C - A)\B 

If you still face any difficulty you can refer to the following documentations:

• https://in.mathworks.com/help/matlab/ref/mldivide.html
• https://in.mathworks.com/help/symbolic/linsolve.html
• https://in.mathworks.com/help/matlab/math/basic-matrix-operations.html