Is there a function $f:\mathbb{R}\to\mathbb{R}$ such that $f\circ f\circ f=Id.$, but $f\neq Id.$?
122160
$f:\mathbb R \to \mathbb R$ be a continuous such that $f(f(f(x)))=x,\forall x \in \mathbb R$ , is $f(x)=x , \forall x \in \mathbb R$?
84143
Given any function $g(x): \mathbb{R} \rightarrow \mathbb{R}$, find a function $f(x)$ such that $f(f(x)) = g(x)$.
155618
Slightly changing the formal definition of continuity of $f: \mathbb{R} \to \mathbb{R}$?
28088
When is $f_{xy}(x,y)\neq f_{yx}(x,y)?$
104757
If $f \circ g$ is surjective, then f is surjective
81799
Examples of functions where $f(ab)=f(a)+f(b)$
80199
Do we have always $f(A \cap B) = f(A) \cap f(B)$?
76148
Show that $\exists c \in \mathbb{R} : f(c) = 0$
27188
Bijection between $\mathbb{R}$ and $\mathbb{R}/\mathbb{Q}$
84189
Is $\mathbb{C}$ equal to $\mathbb{R}^2$?
34260
Injective function from $\mathbb{R}^2$ to $\mathbb{R}$?
127921
Does there exist a function such that $\lim_{x \to a} f(x) = L$ for all $a \in \mathbb R$ but $f(x)$ is never $L$?
124535
continuous function from $[\pi,2\pi]\to \mathbb{R}^2$
110885
Does there exists a continuous surjection from $\mathbb{R}$ to $\mathbb{R}^2$?
62568
Does there exists an entire function $f: \mathbb C \to \mathbb C$ which is bounded on real line and imaginary line?
39090
Finding functions such that $f(g(x)) = f(x)g(x)$
143354
Prove that there exists $c\in\mathbb{R}$ such that $f'(c)=f(c)$