Solving the equation $f(x)=f^{-1}(x)$.
44148
Functions that are their own inverse.
24862
Solving (quadratic) equations of iterated functions, such as $f(f(x))=f(x)+x$
131692
How to show that $f_{0}f_{1}+f_{1}f_{2}+...+f_{2n-1}f_{2n} = f^{2}_{2n}$
76458
Solve the following functional equation $f(xf(y))+f(yf(x))=2xy$
49794
Solve $f(x^2+y+f(y))=2y+f(x)^2$ over $\mathbb{R}$
133333
Find $f(x)$ for $f(f(x))=\sin x$
10024
How to prove $(f \circ\ g) ^{-1} = g^{-1} \circ\ f^{-1}$? (inverse of composition)
134075
Inverse of $A^{-1}+B^{-1}$
155995
Fibonacci proof question: $f_{n+1}f_{n-1}-f_n^2=(-1)^n$
409
functions satisfying $f(x - y) = f(x) f(y) - f(a - x) f(a + y)$ and $f(0)=1$
10068
$f(x,y)= e^{-\frac{1}{x^2+y^2}}$ when $(x,y)\neq (0,0)$ and $f(0,0)=0$.
77071
Solve the functional equation $f(xy) = f(x)f(y) - f(x + y) + 1$ and $f(1) = 2$
108633
Why $f^{-1}(f(A)) \not= A$
98255
Find $f(x)$ such that $f(f(x)) = x^2 - 2$
41226
Find $f:f(xf(x)+f(y))=f(x)^2+y$
59063
$f(f(x))=f(x)$ question
34790
Find $f(1)$ from equation $\int_{0}^{x}f(t)dt = x+\int_{x}^{1}tf(t)dt$