The set of ordered pairs (a, b) of positive real numbers forms a vector space under the following addition and scalar multiplication: (a, b) (c,d) = (ac, bd) c(a, b) = (a, b). What is the additive identity of this vector space? That is, (a,b) = (a,b)? 2. (10 points) Let S = s={ 1²2 1 [1 2 3] [20 -10 4 [B8 9 1]} Write a matrix in span(S) that is 1 not a scalar multiple of either vector in S. Be sure to make clear why your vector is in the span.