Solving functional equations clarification

Question

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how exactly did he apply 1.39 to get

$$f(x-1)^2 =f(1-x)^2$$

From the book Functional equations and how to solve them – Maximilian Janisch Aug 30 '19 at 17:56 — Maximilian Janisch, Aug 30 '19 at 17:56

score 2 · Answer 1 · answered Aug 30 '19 at 08:35

2

It is not difficult; note that $$ f(x-1)^2=f((x-1)^2)=f((1-x)^2)=f(1-x)^2.$$

answered Aug 30 '19 at 08:35

Giuseppe Negro

1 Answers1