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Infinite power tower equal to two

Question

An infinite tower of exponents xxx⋅⋅⋅x^{x^{x^{\cdot^{\cdot^{\cdot}}}}} converges to the value 22. Find xx and give it to the nearest integer.

Short answer

1 (exactly 2≈1.414\sqrt2\approx1.414). The tower equals its own exponent, so if it is 22 then x2=2x^2=2 and x=2x=\sqrt2, which rounds to 11.

Adapted from QuantQuestions.io; question and answer rewritten by SelfMadeQuant.com.

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