Maths Olympiad Prep

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, 2019

Algebra Difficulty 4.6 AIME Prove it United States

Problem:
Let N=2(22)N=2^{\left(2^{2}\right)} and xx be a real number such that N(NN)=2(2x)N^{\left(N^{N}\right)}=2^{\left(2^{x}\right)}. Find xx.

Solution

Solution:
We compute
N (N N ) =16 16 16 =2 4 2 4 2 4 =2 2 2 6 +2 =2 2 66\text{N (N N ) =16 16 16 =2 4 2 4 2 4 =2 2 2 6 +2 =2 2 66}
so x=66x=66.

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