TMUA-P2-PRF2-002 — Paper P2 · Proof by cases · Level 1

Options

1. A
   Only the case $n$ even is needed.
2. B
   $n$ prime and $n$ composite.
3. C
   $n = 0$ and $n \ne 0$.
4. D
   $n$ even ($n = 2k$) and $n$ odd ($n = 2k + 1$), checking $n^2 + n$ in each.
5. E
   $n$ positive and $n$ negative.

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

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