試題詳解

4.Which set is not a vector space?
(A) The set of polynomials of degree exactly 3.
(B) The set of polynomials having'degree 0, 1, 2, or 3, together with the 0-polynomial.
(C) The set of all vectors (x₁, x₂, x₃, x₄) in R⁴ such that x₂ = 5x₃ - 7x₄.
(D) The set of all vectors of the form [a+b³, a-b³, 2a] in R³.
(E) The set of all vectors [a+b³, a-b³] in R².