{"id":10361,"date":"2022-04-02T21:19:25","date_gmt":"2022-04-02T15:49:25","guid":{"rendered":"https:\/\/mathemerize.com\/?p=10361"},"modified":"2022-04-05T18:23:48","modified_gmt":"2022-04-05T12:53:48","slug":"use-euclids-division-lemma-to-show-that-the-square-of-any-positive-integer-is-either-of-the-form-3m-or-3m-1-for-some-integer-m","status":"publish","type":"post","link":"https:\/\/mathemerize.com\/use-euclids-division-lemma-to-show-that-the-square-of-any-positive-integer-is-either-of-the-form-3m-or-3m-1-for-some-integer-m\/","title":{"rendered":"Use Euclid’s Division Lemma to show that the square of any positive integer is either of the form 3m or 3m + 1 for some integer m."},"content":{"rendered":"
By Euclid’s Division Algorithm, we have<\/p>\n
a = bq + r\u00a0 \u00a0 \u00a0 \u00a0…………..(i)<\/p>\n
On putting b = 3 in (1), we get<\/p>\n
a = 3q + r,\u00a0 \u00a0 \u00a0 [0 \\(\\le\\) r < 3]<\/p>\n
If r = 0\u00a0 \u00a0a = 3q\u00a0 \\(\\implies\\)\u00a0 \\(a^2\\) = \\(9q^2\\)\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0…..(2)<\/p>\n
If r = 1\u00a0 a = 3q + 1\u00a0 \u00a0\\(\\implies\\)\u00a0 \\(a^2\\) = \\(9q^2 + 6q + 1\\)\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0…..(3)<\/p>\n
If r = 2\u00a0 \u00a0a = 3q + 2\u00a0 \u00a0 \\(\\implies\\)\u00a0 \\(a^2\\) = \\(9q^2 + 12q + 4\\)\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0…..(4)<\/p>\n
From (2), \\(9q^2\\) is a square of the form 3m, where m = \\(3q^2\\)<\/p>\n
From (3), \\(9q^2 + 6q + 1\\)\u00a0 i.e. , 3(\\(3q^2 + 2q\\)) + 1 is a square which is of the form 3m + 1 where m = \\(3q^2 +2q\\)<\/p>\n
From (4), \\(9q^2 + 12q + 14\\)\u00a0 i.e. , 3(\\(3q^2 + 2q + 1\\)) + 1 is a square which is of the form 3m + 1 where m = \\(3q^2 +4q + 1\\)<\/p>\n
Therefore, the square of any positive integer is either of the form 3m or 3m + 1 for some integer m.<\/strong><\/p>\n","protected":false},"excerpt":{"rendered":" Solution : By Euclid’s Division Algorithm, we have a = bq + r\u00a0 \u00a0 \u00a0 \u00a0…………..(i) On putting b = 3 in (1), we get a = 3q + r,\u00a0 \u00a0 \u00a0 [0 \\(\\le\\) r < 3] If r = 0\u00a0 \u00a0a = 3q\u00a0 \\(\\implies\\)\u00a0 \\(a^2\\) = \\(9q^2\\)\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 …<\/p>\n