Maths Olympiad Prep

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Number theory Difficulty 5.7 AIME, harder Prove it

5. Prove: When m>2m>2, 02,12,,(m1)20^{2}, 1^{2}, \cdots,(m-1)^{2} cannot be a complete residue system modulo mm.

Solution

5. Since j2(mj)2(modm)j^{2} \equiv (m-j)^{2} \pmod{m}.

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Source: NuminaMath-1.5, licensed Apache-2.0. Statement and solution reproduced as published; topic and difficulty added by this site.