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Find the area of a subset of a complex plane

Source: Bangladesh Mathematical Olympiad 2020 Problem 7

February 19, 2022
geometrycoordinate geometryalgebra

Problem Statement

ff is a function on the set of complex numbers such that f(z)=1/(z)f(z)=1/(z*), where zz* is the complex conjugate of zz. SS is the set of complex numbers zz such that the real part of f(z)f(z) lies between 1/20201/2020 and 1/20181/2018. If SS is treated as a subset of the complex plane, the area of SS can be expressed as m×πm× \pi where mm is an integer. What is the value of mm?