How many functions, $f(x) = f'(x)$?
10431
Prove that $C\exp(x)$ is the only set of functions for which $f(x) = f'(x)$
17154
Does a non-trivial solution exist for $f'(x)=f(f(x))$?
66772
$f(f(x)f(y))+f(x+y)=f(xy)$
132113
Does $f(x) = f(2x)$ for all real $x$, imply that $f(x)$ is a constant function?
1071
Determine all functions $f:\mathbb{N}\rightarrow\mathbb{N}$ such that $xf(y)+yf(x)=(x+y)f(x^2+y^2)$ for all $x,y\in\mathbb{N}$ (contest question)
133682
Prove that if $f(t)$ satisfies $f(t)=f'(t)$, then $f(t+s)=f(t)f(s)$ for all $t,s\in R$ without using the fact that $f(t)=c\cdot e^t$.
104263
How to show that $f'(x)<2f(x)$
55175
Is the function $f(x) = x^2 - 2x$ one-to-one?
112636
How many continuous function $f(x)$ exist such that $\int_{0}^{1}f(x)\big(1-f(x)\big)\mathrm dx = \frac{1}{4}$?
42218
How to find out the following function f which is a function of r?
47688
Number of roots of differentiable function
69008
$f'(x) = [f(x)]^{2}$. Prove $f(x) = 0 $
55840
Number of functions from n-element set to {1, 2, …, m}
409
functions satisfying $f(x - y) = f(x) f(y) - f(a - x) f(a + y)$ and $f(0)=1$
110704
Find all functions $f$ such that $f(x)+f(\frac{1}{1-x})=x$
41226
Find $f:f(xf(x)+f(y))=f(x)^2+y$
51291
How can I express $\int \frac{1}{f'(x)}$ in terms of $f(x)$