Solving $f'(x) = f(f(x))$
17154
Does a non-trivial solution exist for $f'(x)=f(f(x))$?
104278
Finding function $f(x)$ which satisfy given functional equation
106830
are $f(f(x))=f(x)$ and $f(x)=x$ equivalent?
156778
Finding functions satisfying $f(f(x))+f(x)+x=0$
26677
thoughts about $f(f(x))=e^x$
34790
Find $f(1)$ from equation $\int_{0}^{x}f(t)dt = x+\int_{x}^{1}tf(t)dt$
112923
Let $f:\mathbb{R}\longrightarrow \mathbb{R}$ a differentiable function such that $f'(x)=0$ for all $x\in\mathbb{Q}$
103251
Solution(s) to $f(x + y) = f(x) + f(y)$ (and miscellaneous questions...)
48652
Solve the functional equation $2f(x)=f(ax)$ for some $a$.
48592
Prove that $f'$ exists for all $x$ in $R$ if $f(x+y)=f(x)f(y)$ and $f'(0)$ exists
42699
Solve for $f(x)$ if $f(f(x))=6x-f(x)$
31685
Differentiability of $f(x) = x^2 \sin{\frac{1}{x}}$ and $f'$
103706
If $\{f(0)\}^{2} + \{f'(0)\}^{2} = 4$ then there is a $c$ with $f(c) + f''(c) = 0$
79212
Find the general solution of $y'= a^{x + y}$ where y is the function
111789
Solving functional differential equation $f'(x)=2f(2x)-f(x)$
116946
Ordinary differential equation $y'(t)=\sin(f(t,y))$
51291
How can I express $\int \frac{1}{f'(x)}$ in terms of $f(x)$