A basis for a vector space has three properties.there is a space V=Q^4 over Q .
there is a series of vectors (v1 ,v2 ,v3,v4,v5)
that spans V
does the series
(v1 ,v2 ,v3,v4) is a basis of V?
if it is explain
if not give a counter example??
we could have that v5 is a linear combination of others.