Suggest the vectors a = (1,2,0,1), b = (0,-2,-1,1), c = (1,4,1,0) and d = (2,1,0,1) in R4.
(a) Is d in the span of a,b and c?
(b) Show that the four vectors are linearly dependent.
(c) Express one of the four vectors as the linear combination of the others.