how can i multiply two matrices?

I have a matrix 'a' with size 3x3 and 'b' with size 3x1.i want to multiply the inverse of 'a' with matrix 'b'.I tried the below code but got an error "Matrix dimensions must agree". please help to solve this

    a=[1 0 -3; 2 -2 1; 0 -1 3];
    inv_a=inv(a);
    b=[0;2;121];
    c=inv_a.*b;

[Beder]

This code does not produce any error on my system. Maybe you have a variable called "inv" which overlays the function "inv"?

[Walter Roberson]

Beder,

I suspect you are using R2016b, which introduced automatic vector expansion as if bsxfun() had been used.

Answer 1

[Walter Roberson]

    c=inv_a * b;

not .*

inv_a is a 3 x 3 matrix, and you want algebraic matrix multiplication by the 3 x 1 matrix b in order to get the 3 x 1 solution.

[Naseeba PP]

Thank you

Answer 2

[Alicia Palmerin-Jimenez]

no