# What's the domain for the given function?

• Dec 4th 2012, 09:39 AM
theunforgiven
What's the domain for the given function?
Hey everyone, My friend and I are being asked to find the domain for the following function and it's derivatives:
http://img27.imageshack.us/img27/4629/fnction.jpg
From what I can tell, it's R any real number, but my friend insists it's R any real number AND X doesn't equal -1. Who's correct?
• Dec 4th 2012, 09:45 AM
HallsofIvy
Re: What's the domain for the given function?
Just do the arithmetic: what is f(1)? What is f(0)?

Or, perhaps, what is your understanding of the domain of a function?
• Dec 4th 2012, 09:51 AM
theunforgiven
Re: What's the domain for the given function?
Quote:

Originally Posted by HallsofIvy
Just do the arithmetic: what is f(1)? What is f(0)?

Or, perhaps, what is your understanding of the domain of a function?

To answer your question, the domain of a function, as far as I'm concerned, is a set of possible values where the function is defined.
f(1) is 0/1 which is zero. f(0) is -1/0 which is undefined... Guess that answers my question. :) It's R any real number expect x=0. We thought the f'(x) and f"(x) had something to do with the domain, but I guess we were wrong.
• Dec 4th 2012, 04:48 PM
sjmiller
Re: What's the domain for the given function?
Quote:

Originally Posted by theunforgiven
To answer your question, the domain of a function, as far as I'm concerned, is a set of possible values where the function is defined.
f(1) is 0/1 which is zero. f(0) is -1/0 which is undefined... Guess that answers my question. :) It's R any real number expect x=0. We thought the f'(x) and f"(x) had something to do with the domain, but I guess we were wrong.

Given a function f:X→Y, the set X is the domain of f; the set Y is the codomain of f. The domain is the set of 'input' values for which the function is defined. Therefore for each element of the domain, there is a corresponding element in the codomain.

For the first function it is defined for all x if x does not equal 0.