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Show that every positive integer is odd or even |
| Answer» According to the question, we have to show that every positive integer is either even or odd.Let us assume that there exists a smallest positive integer that is neither odd nor even, say n. Since n is the least positive integer which is neither even nor odd, n - 1 must be either odd or even.Case 1: If n - 1 is even, n - 1 = 2k for some k.But this implies n = 2k + 1This implies n is odd.Case 2: If n - 1 is odd, n - 1 = 2k + 1 for some k.But this implies n = 2k + 2 = 2(k + 1)This implies n is even.Therefore,In both cases , we arrive at a contradiction.Thus, every positive integer is either even or odd | |