Re: Is W a subspace of V?

Hey TimsBobby2.

Can you show us an attempt to prove your statements with the appropriate vector space axiom?

Re: Is W a subspace of V?

1) yes, multiplying by a negative scalar ruins everything.

2) is it closed under polynomial addition? is it closed under scalar multiplication? (recall that (cp)(x) = c(p(x)) for all x). is the 0-polynomial in W?

you might want to ask yourself: for the polynomial p(x) = x in Z[x], is (1/2)p(x) in Z[x]?

Re: Is W a subspace of V?

So for 2) if I consider W and I do scalar multiplication by 1/2, (1/2)p(x) is not in Z[x], so W is not a subspace of V? Is that correct to say (I'm just starting this stuff today)

Re: Is W a subspace of V?

what do you think? i'm not trying to be mean....i'm asking you to convince yourself that what you say is true. the truth of math doesn't depend on "who the expert is", it should be self-evident. if you are unsure about something, ask about that. understanding the ideas is the important part....getting the answers correct is only a useful by-product.