What is the domain of #f(x) = x#?

1 Answer
Aug 3, 2014

All real values of #x#.

The "domain" of a function is the set of values that you can put into the function such that the function is defined. It's easiest to understand this in terms of a counter-example. For instance, #x=0# is NOT part of the domain of #y=1/x#, because when you put that value into the function, the function isn't defined (i.e. #1/0# isn't defined).

For the function #f(x)=x#, you can put any real value of #x# into #f(x)# and it will be defined - so that means the domain of this function is all real values of #x#.