Is there a function $f$ or $g$ that makes this true?
6396
If two limits don't exist, are we sure the limit of sum doesn't exist?
47166
Is there a function whose inverse is exactly the reciprocal of the function, that is $f^{-1} = \frac{1}{f}$?
64836
Functions that are always less than their derivatives
76249
Does the limit of function of two variables exist
103568
Possibility of finding a such function?
45222
When $f(x) = g(y)$ for almost every $(x,y)$, must $f$ and $g$ be constant almost everywhere?
98255
Find $f(x)$ such that $f(f(x)) = x^2 - 2$
4296
If $f,g$ are entire functions and$\ fg\equiv 0$ then either $f \equiv 0$ or $g\equiv0. $
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 $f(x,y)=xy\, g(x,y)$
97772
An example of a function which satisfies $\sup_{y}\inf_{x}f(x,y)<\inf_{x}\sup_{y}f(x,y)$
28011
Does there exists an entire function such that for each $|z|>C$ for some constant $C$, $|f(z)|=|z|+1$?
139531
If $f'/f=g'/g$ at every $1/n$ then $f=kg$ for some complex number $k$
83036
f(g(x)) has a degree divisible by n
11828
continuous functions on $\mathbb R$ such that $g(x+y)=g(x)g(y)$
29647
Do there exist functions satisfying $f(x+y)=f(x)+f(y)$ that aren't linear?
74810
A function $f$ such that $f' = 0$ when $x < 0$ and $f' = 1$ when $x \geq 0$?
119042
If $f+g$ and $f$ are differentiable at $a$, must $g$ be differentiable at $a$?