# Thread: does anyone know what this means?

1. ## does anyone know what this means?

Given to me by my math teacher. We were told it was some kind of proof but I dont really understand what it means...

pf (f^1 (x)) = x

any ideas?

Thanks guys

2. What's the context? "pf" could mean "probability function", apart from that I haven't a clue. What level of mathematics - grade school, high school, university, postgrad? What field: probability/statistics, analysis, calculus, graph theory, topos theory, what?

3. College pre-calculus and we are working on function, maxima, stretching, that kind of thing. thank you for answering...

4. Originally Posted by tara
Given to me by my math teacher. We were told it was some kind of proof but I dont really understand what it means...

pf (f^1 (x)) = x

any ideas?

Thanks guys
ok, so i do not know what "pf" is supposed to mean. perhaps you copied it wrong. this may have to do with inverse functions, that's the closest thing i see to this.

note that if $f(x)$ and $f^{-1}(x)$ (the usual notation for inverse functions) are inverses of each other, then:

$f(f^{-1}(x)) = x$ and $f^{-1}(f(x)) = x$ ..........that is, the composition of a function and it's inverse remains fixed. whatever the input is, that's what the output will be