Question

a)

Let E and F be two subspaces of R^n. Define
EnF = {u such that u is and element of E and u is an element ofF}
and
E + F = {w = u + v; where u is an element of E and v is an elementof F}

Show that EnF and E+F are subspaces of R^n

b)

Let {u,v,w} be a linearly independent set of vectors of R^4. Let E= span{u,2v} and F=span{w,v}. Find EnF and E + F.


Thanks for your help, I have NO idea what i'm doing here.