find all functions $ f : \mathbb{R} \rightarrow \mathbb{R} $ such that : $ f(f(x))=x^2-2 $
98255
Find $f(x)$ such that $f(f(x)) = x^2 - 2$
156778
Finding functions satisfying $f(f(x))+f(x)+x=0$
5419
Continuous functions with $f^2(x)=g^2(x)\neq 0$
11453
Find a real function $f:\mathbb{R}\to\mathbb{R}$ such that $f(f(x)) = -x$?
25953
Solving a functional relation $f\left( x \cdot f(y)\right)=x^2 \cdot y^a$
142682
Find $f(x)$ where $ f(x)+f\left(\frac{1-x}x\right)=x$
55175
Is the function $f(x) = x^2 - 2x$ one-to-one?
82597
How to find $ f(x)$ if $f(1-f(x))=x$ for all $x$ $\in \mathbb{R}$
31698
$f(m^2 + f(n)) = f(m)^2 + n$ for all natural numbers
144473
Finding all functions $ f : \mathbb N^*\to\mathbb N^*$ such that for every $ x , y \in \mathbb N ^ * $, $ f ( x ) + f ( y ) \mid x ^ n + y ^ n $
14975
Functions satisfying $f:\mathbb{N}\rightarrow\ \mathbb{N}$ and $f(f(n))+f(n+1)=n+2$
62709
Functions that are sets of all function - proofs
68165
Find a function $f: \mathbb{R} \to \mathbb{R}$ that is continuous at precisely one point?
75448
Find all function satisfying $f(f(n))+f(n)=2n+3k$
44293
Functions satisfying $f\left( f(x)^2+f(y) \right)=xf(x)+y$
118154
$f: \mathbb{R} \to \mathbb{R}$ that takes each value in $\mathbb{R}$ twice
23186
$f: \mathbb{R^2} \to \mathbb{R}$ a $C^\infty$ function such that $f(x,0)=f(0,y)=0$ then exists $g$ such that $f(x,y)=xy\, g(x,y)$