One option is to concatenate them and then use the rank function to check to see if they are linearly dependent.
For this particular problem, this works:
a = [1;2;3];
b = [2;4;6];
c = [a b];
LinDep = rank(c) < min(size(c))
Here, if ‘LinDep’ (‘linearly dependent’) is true (or 1), at least two columns or rows are multiples of each other.
