Example 5 Let be a positive integer greater than 2. Prove: there exists a prime , such that .
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Example 5 Let be a positive integer greater than 2. Prove: there exists a prime , such that .
The text is translated while preserving the original line breaks and format.
Proof: Let be all the prime numbers not exceeding , and let be the smallest prime number greater than . If , then , and the proposition holds. If , then , and the proposition holds. When , both appear in , so , thus . Therefore, the proposition holds.