I want to find the function $f(x)$ that satisfies the equation.
30695
Can I solve this differential equation at a point?
129052
Find all functions satisfying $\frac{1}{f(a)}+ \frac{1}{f(b)} = \frac{1}{f(c)} $ whenever $\frac{1}{a}+ \frac{1}{b} = \frac{1}{c} $
133333
Find $f(x)$ for $f(f(x))=\sin x$
129599
Functional Equation: Find all functions $f: \mathbb{R} \rightarrow \mathbb{R}$ such that $(x+y)(f(x)-f(y))=(x-y)f(x+y)$
139019
Polynomial satisfying $f(x) = f'(x) \cdot f''(x)$
74810
A function $f$ such that $f' = 0$ when $x < 0$ and $f' = 1$ when $x \geq 0$?
24862
Solving (quadratic) equations of iterated functions, such as $f(f(x))=f(x)+x$
2717
Help proving existence of an specific $x_0$ for which $f''(x_0)=0$
74100
How do you solve $f'(x) = f(f(x))$?
42699
Solve for $f(x)$ if $f(f(x))=6x-f(x)$
99917
What function satisfies $F'(x) = F(2x)$?
31319
An integrable and periodic function $f(x)$ satisfies $\int_{0}^{T}f(x)dx=\int_{a}^{a+T}f(x)dx$.
117353
Polynomial equation $f(x)f(2x^2)=f(2x^3+x)$
17175
Problem in solving functional equation $f(x^2 + yf(x)) = xf(x+y)$
37976
Find all functions $f$ such that $(x+y)f(x)+f(y^2)=(x+y)f(y)+f(x^2)$
24553
$f$ has the form $f(x) =ax^2+bx+c$.
72769
How find this function $xf(x^2)=f(x),x>0$