# Thread: determine the range of ln equations

1. ## determine the range of ln equations

I need to determine the ranges of values of x and y for which the expressions on each side are defined please can I have help to start this off having a very bad day

3ln(y+4)=2ln(x+2)-2ln(x+9)+3ln(x2-1)

2. It's defined when the argument is greater than 0.

$\displaystyle y +4 > 0$

$\displaystyle x+2 > 0$
$\displaystyle x+9 > 0$
$\displaystyle x^2-1 > 0$

Incidentally does anyone know how to get those in a table, like in matrices?

3. Use the following:

$\displaystyle \exists\;{\log u} \Leftrightarrow u>0$

Fernando Revilla

Edited: Sorry, I didn't see e^(i*pi)'s post

4. Originally Posted by e^(i*pi)
Incidentally does anyone know how to get those in a table, like in matrices?
Do you mean something lihe this?

$\displaystyle \begin{tabular}{| c | c | c | c | } \hline {$y+4>0$} & {$x+2>0$} & {$x+9>0$} & {$x^2-1>0$} \\ \hline {$y>-4 $}&{$\ldots$}&{$\ldots $}&{$\ldots $} \\ \hline \end{tabular}$

Fernando Revilla

5. Originally Posted by FernandoRevilla
Do you mean something lihe this?

$\displaystyle \begin{tabular}{| c | c | c | c | } \hline {$y+4>0$} & {$x+2>0$} & {$x+9>0$} & {$x^2-1>0$} \\ \hline {$y>-4 $}&{$\ldots$}&{$\ldots $}&{$\ldots $} \\ \hline \end{tabular}$

Fernando Revilla
I mean where they're under each other in a line. It doesn't really matter that much, I think I made my point but thanks anyway