(a) Let S be a subspace of Rn for some positive integer n. Show that if S contains the vectors e1,,en, then it equals Rn (recall that ei denotes the vector in Rn whose i th entry is 1 and whose remaining entries are all 0). (b) Show that Span110,110,111=R3. (c) Is 110,110,111 a basis of R3? Justify your answer. 5. [8] Let S be a 2-dimensional subspace of Rn for some positive integer n. Show that if {u,v} is a basis of S, then {u,u+v} is also a basis of S