domain problem

Printable View

September 30th 2009, 07:23 PM
oblixps

domain problem

if the domain of f(x) is (-1,1) then what is the domain of f((x+1)/(x-1))?

i don't even know how to start this problem. all i know is that x cannot be equal to 1.
September 30th 2009, 09:01 PM
mr fantastic

Quote:

Originally Posted by oblixps

if the domain of f(x) is (-1,1) then what is the domain of f((x+1)/(x-1))?

i don't even know how to start this problem. all i know is that x cannot be equal to 1.

The required domain will be the range of the function $y = \frac{x + 1}{x - 1}$ over the interval $-1 < x < 1$ . The best way of finding a range is to draw a graph.
September 30th 2009, 10:37 PM
A Beautiful Mind

What is this? A rational function?

'Cause the way I find is that you take the bottom part and whatever turns out to be zero is what makes the domain...

Did you need to rewrite it in a different notation?

$(-\infty, 1) \cup (1, \infty)$
September 30th 2009, 10:38 PM
mr fantastic

Quote:

Originally Posted by A Beautiful Mind

What is this? A rational function?

'Cause the way I find is that you take the bottom part and whatever turns out to be zero is what makes the domain...

Did you need to rewrite it in a different notation?

$(-\infty, 1) \cup (1, \infty)$

Read the question carefully. Your reply to it is irrelevant.
October 1st 2009, 10:16 PM
CaptainBlack

Quote:

Originally Posted by oblixps

if the domain of f(x) is (-1,1) then what is the domain of f((x+1)/(x-1))?

i don't even know how to start this problem. all i know is that x cannot be equal to 1.

The domain of:

$g(x)=f\left( \frac{x+1}{x-1} \right)$

will be the set of all real numbers $x$ such that:

$y=\frac{x+1}{x-1} \in (-1,1)$

CB

All times are GMT -8. The time now is 12:59 AM.