|Let W1 and W2 be subspaces of a vector spaces V. Define W1+W2 = {v | v= wi + w2 where wi E Wi and w2 E W2} a) Prove that W1 + W2 is a subspace of V. b) Prove that any subspaces of V that contains both W1 and W2 must also contain W1 +W2.
can someone please show me how to do this?