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Part BCSIR NET December 2024the-dual-of-a-span-not-of-the-ambient-space

The dual of a span not of the ambient space

Let U denote the span of {eᵗ, ᵗ, ᵗ} in the real vector space of continuous functions from to . Consider the vector spaces V = { | f is an linear transformation} and W = {f ∈ V | ᵗ) = 0}. Which of the following statements is true?

  1. A.Both V and W are infinite-dimensional
  2. B.dim V = 3 and dim W = 1
  3. C.dim V = 3 and dim W = 2
  4. D.V is infinite-dimensional and dim W = 0

You have the answer. Trap Analysis is why the other three were written.

Not a worked solution repeated four times — the specific reasoning error each wrong option was built to reward.

See pricing

50 are analysed free — try those first.

Related counterexample: An injective linear operator on a vector space is surjective

More on this topic

The chapter behind this: Bases, dimension and rank — free to read

From Vector Spaces and Linear MapsBases, dimension, rank–nullity

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