Reading the world through functions
A journey into the world of functions, from concept to application.

The concept of 'function' is widely used in various fields, such as 'the functional relationship between exercise and weight,' 'the functional relationship between income and happiness,' 'the functional relationship between news and public opinion,' and 'the functional relationship between welfare and politics.'
Although function is clearly a mathematical term, it is also a concept that is used quite a bit in fields other than mathematics.
The concept of a commonly used function like this doesn't seem that difficult when used without much thought.
But when someone asks about the concept, it's not easy to explain.


Professor Lee Han-jin, who has told interesting and engaging stories about mathematics through 『How Mathematics Became Art』 and 『Mathematics Gallery』, has published a new book, 『So What is a Function?: A Mathematician's Story of Functions』, which provides a friendly explanation of functions, which everyone seems to know but are not easy to explain.
Functions are one of the most representative and widely applicable mathematical concepts learned in school.
This book explains why functions are essential knowledge for us, how the concept of functions entered our lives, and what we need to consider when dealing with functions mathematically.
We explore functions in a variety of fields, including functions found in everyday life, such as calculating calories and predicting arrival times, predicting braking time based on speed, implementing animation motion, optimizing product prices, and addressing oil depletion and environmental issues.
It shows that functions can be useful tools for everything from everyday to specialized tasks, from simple to complex.
It also tells how the concept of function was established from the perspective of the history of mathematics, from Tartaglia to Galileo to Descartes to Fermat, and provides a mathematical perspective on the world through the concepts of relatively simple functions, such as linear and quadratic functions.


Functions are not far away, they are close to our daily lives.
As you follow the fascinating stories of functions told in this book, from art and sports to self-driving cars, you will not only learn how to use functions as useful tools, but also learn what mathematics is through functions and gain a useful mathematical perspective on the world.