My first thought is to do this with arrayfun using an anonymous function that adds each scalar element of a to the full array in b. Then since you get a cell array result you can expand that cell array into the array you are looking for:
>> a=[1,2,3,4], b=[5,6,7]
>> result = arrayfun(@(x) x+b, a,'UniformOutput',false);
>> result = [result{:}]
result =
6 7 8 7 8 9 8 9 10 9 10 11
1
solved Im looking for a way to add up elements of two arrays