Moderate -0.5 This requires testing small values of n to find a counterexample. While it involves understanding primes and systematic checking, finding n=10 gives 121=11² is straightforward and requires minimal calculation. It's easier than average as it's a simple disproof by counterexample with no complex reasoning needed.
Take \(n = 11\); the result is divisible by 11. (\(n = 10\) is the smallest number)
M1A1
Total: 2
## Question 1:
| Answer | Mark | Guidance |
|--------|------|----------|
| Take $n = 11$; the result is divisible by 11. ($n = 10$ is the smallest number) | M1A1 | |
| | **Total: 2** | |
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1 John asserts that the expression $n ^ { 2 } + n + 11$ is prime for all positive integer values of $n$. Show that John is wrong in his assertion.
\hfill \mbox{\textit{OCR MEI C3 Q1 [2]}}