- #1
dragonxhell
- 21
- 0
Could someone help me with this question? Because I'm stuck and have no idea how to solve it & it's due tomorrow :(
Let S be the following subset of the vector space P_3 of all real polynomials p of degree at most 3:
S={p∈ P_3 p(1)=0, p' (1)=0}
where p' is the derivative of p.
a)Determine whether S is a subspace of $P_3$
b) determine whether the polynomial q(x)= x-2x^2 +x^3 is an element of S
Attempt:
I know that for the first part I need to proof that it's none empty, closed under addition and multiplication right?
will this give me full mark for the part a if I answer like this:
(af+bg)(1)=af(1)+bg(1)=0+0=0 and
(af+bg)′(1)=af′(1)+bg′(1)=0+0=0
so therefore it's a subspace of P_3?
b) i got no idea...
Thank you very much!
Let S be the following subset of the vector space P_3 of all real polynomials p of degree at most 3:
S={p∈ P_3 p(1)=0, p' (1)=0}
where p' is the derivative of p.
a)Determine whether S is a subspace of $P_3$
b) determine whether the polynomial q(x)= x-2x^2 +x^3 is an element of S
Attempt:
I know that for the first part I need to proof that it's none empty, closed under addition and multiplication right?
will this give me full mark for the part a if I answer like this:
(af+bg)(1)=af(1)+bg(1)=0+0=0 and
(af+bg)′(1)=af′(1)+bg′(1)=0+0=0
so therefore it's a subspace of P_3?
b) i got no idea...
Thank you very much!