row vector and column vector addition

I dont understand why I'm able to add rowvector w to columnvector v. I should get an error right?

w = [1 2 3];

v = [4;5;6];

x = v + w

x =

5 6 7

6 7 8

7 8 9

Answer 1

[Stephen23]

"I should get an error right?"

Not since R2016b:

https://blogs.mathworks.com/loren/2016/10/24/matlab-arithmetic-expands-in-r2016b/

The documentation explains what size arrays can be used together with such operators:

https://www.mathworks.com/help/matlab/matlab_prog/compatible-array-sizes-for-basic-operations.html

Note also that the plus documentation includes links to that second page (the links are within the descriptions of both of the input arguments). This is why it is strongly recommended to read the documentation for all operators that you use, no matter how trivial you may think that operator is: reading the documentation significantly reduces surprises.