How to approach an equation of the form $f(x)=y$ where $f$ is recursively defined?
11976
Help with a recurrence with even and odd terms
79212
Find the general solution of $y'= a^{x + y}$ where y is the function
27809
Find the function equation $f(x+f(y)+yf(x))=y+f(x)+xf(y)$
136475
d'Alembert-like functional equation: $f(x+y)+g(x-y)=\lambda f(x)g(y)$
122329
Determine all functions $f(x)$ such that $f(f(x+y))=f(x)+f(y)$
8276
How do I get my equation to have the form $(x-a)^2 + (y-b)^2 + (z-c)^2-d = 0$?
73073
Differentiating $y=x^{2}$
66772
$f(f(x)f(y))+f(x+y)=f(xy)$
155806
(Olympiad Question) $f(2x) + 2f(y) = f(f(x+y))$
65946
A function $f: \mathbb R \to \mathbb R$ satisfies equation $f(x+y)=f(x)f(y)$ for all $x,y\in \mathbb R $
115466
How make f[{x,y}] evaluate as f[x,y]?
103251
Solution(s) to $f(x + y) = f(x) + f(y)$ (and miscellaneous questions...)
129599
Functional Equation: Find all functions $f: \mathbb{R} \rightarrow \mathbb{R}$ such that $(x+y)(f(x)-f(y))=(x-y)f(x+y)$
124523
Finding an Inverse Function and Composition of Functions?
66406
How to calculate $f(x)$ in $f(f(x)) = e^x$?
409
functions satisfying $f(x - y) = f(x) f(y) - f(a - x) f(a + y)$ and $f(0)=1$
71807
Defining a function by equations with different number of arguments