Maths Olympiad Prep

Library / /18 of 520

Number theory Difficulty 5.3 AIME, harder Find the answer

1. Using the properties of indices and Example 1 in §3, construct a table of indices modulo 23 with base 11.

A number or a short expression. Fractions can be typed as 3/2, and spacing doesn't matter.

Solution

1. From γ23,11(5)γ23,5(11)1(mod22)\gamma_{23,11}(5) \cdot \gamma_{23,5}(11) \equiv 1(\bmod 22), we get γ23,11(5)=5\gamma_{23,11}(5)=5, hence γ23,11(a)5γ23,5(a)(mod22)\gamma_{23,11}(a) \equiv 5 \gamma_{23,5}(a)(\bmod 22).
a -11 -10 -9 -8 -7 -6 -5 -4 -3 -2 -1 23.11 (a) 12 4 17 19 18 18 16 9 3 21 11 a 1 2 3 4 5 6 7 8 9 10 11 23.11 (a) 0 10 14 20 5 2 7 8 6 15 1\text{a -11 -10 -9 -8 -7 -6 -5 -4 -3 -2 -1 23.11 (a) 12 4 17 19 18 18 16 9 3 21 11 a 1 2 3 4 5 6 7 8 9 10 11 23.11 (a) 0 10 14 20 5 2 7 8 6 15 1}

Want a route through all this instead of an archive? The track puts 2,000 problems in a working order, from AMC 10 level to the IMO shortlist.

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