Ive been shown that a function can be written like so

Question

f:X->Y,f(x)=rule

where X is the Domain and Y, the co-domain. Firstly, what is the co-domain? Ive tried looking it up but all I get is "the set of which y values fall in".

If that is the case, say for the function, y=1/(x-1), do I write it like this

f:R\{1}->R\{0},f(x)=1/(x-1)

or instead of R\{0}, just

f:R\{1}->R,f(x)=1/(x-1)?? Where R is the set of all real numbers.

And please, if the answer is both, which would be "more right"?

Answer 1

i don't really know because one where is your numbers at