TMUA-P2-ERR1-007 — Paper P2 · Identifying errors in proofs · Level 2

Options

1. A
   The proof checks only the even case and omits the odd case; moreover the claim itself is false (e.g. $n = 2$ gives $6$, which is even).
2. B
   The proof is valid and the claim is true.
3. C
   The fault is that $k$ might not be an integer.
4. D
   A proof by contradiction was required.
5. E
   The algebra is wrong: $4k^2 + 2k$ is odd.

Letters only — the answer key is hidden. Work it out, then check the solution below.

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