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# Found this gem when looking for STEP preparation material watch

1. A mathematician, a physicist and an engineer enter a mathematics contest, the first task of which is to
prove that all odd number are prime. The mathematician has an elegant argument: ‘1’s a prime, 3’s a prime,
5’s a prime, 7’s a prime. Therefore, by mathematical induction, all odd numbers are prime. It’s the physicist’s
turn: ‘1’s a prime, 3’s a prime, 5’s a prime, 7’s a prime, 11’s a prime, 13’s a prime, so, to within experimental
error, all odd numbers are prime.’ The most straightforward proof is provided by the engineer: ‘1’s a prime,
3’s a prime, 5’s a prime, 7’s a prime, 9’s a prime, 11’s a prime . . . ’.
2. (Original post by CancerousProblem)
A mathematician, a physicist and an engineer enter a mathematics contest, the first task of which is to
prove that all odd number are prime. The mathematician has an elegant argument: ‘1’s a prime, 3’s a prime,
5’s a prime, 7’s a prime. Therefore, by mathematical induction, all odd numbers are prime. It’s the physicist’s
turn: ‘1’s a prime, 3’s a prime, 5’s a prime, 7’s a prime, 11’s a prime, 13’s a prime, so, to within experimental
error, all odd numbers are prime.’ The most straightforward proof is provided by the engineer: ‘1’s a prime,
3’s a prime, 5’s a prime, 7’s a prime, 9’s a prime, 11’s a prime . . . ’.
3. (Original post by lizard54142)
4. uhm what?
5. (Original post by CancerousProblem)
A mathematician, a physicist and an engineer enter a mathematics contest, the first task of which is to
prove that all odd number are prime. The mathematician has an elegant argument: ‘1’s a prime, 3’s a prime,
5’s a prime, 7’s a prime. Therefore, by mathematical induction, all odd numbers are prime. It’s the physicist’s
turn: ‘1’s a prime, 3’s a prime, 5’s a prime, 7’s a prime, 11’s a prime, 13’s a prime, so, to within experimental
error, all odd numbers are prime.’ The most straightforward proof is provided by the engineer: ‘1’s a prime,
3’s a prime, 5’s a prime, 7’s a prime, 9’s a prime, 11’s a prime . . . ’.
This is in one of the Siklos booklets. Initially it's funny, but if you think about it on a more practical level none of the three arguments are in the true spirit of their respective field.
1. Induction doesn't work like that. You have to prove that the result being true for one integer implies the result is true for the next. This is impossible in this case.
2. The physicist neglected experimental data within the recorded range.
3. The engineer doesn't know .

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