Homework Help: Use the properties of logarithma to xpand the logarithmic function

1. Nov 19, 2009

Ki-nana18

1. The problem statement, all variables and given/known data
Use the properties of logarithma to xpand the logarithmic function ln[(x2+1)(x-1)]

2. Relevant equations

3. The attempt at a solution
[ln x2+ln 1]+[ln x-ln 1]
2 ln x+ln x

2. Nov 19, 2009

gamer_x_

the first step makes sense: $$ln[(x^2+1)(x-1)]=ln(x^2+1)+ln(x-1)$$

but then you continued: $$ln(x^2+1)=ln(x^2)+ln(1)$$

You can't do that, but you can do something else to the $$x^2+1$$...

3. Nov 19, 2009

Staff: Mentor

Is the something else you're thinking about factoring x^2 + 1?

4. Nov 20, 2009

gamer_x_

I just realized I was stupidly thinking of $$x^2-1$$ not $$x^2+1$$. You can't really factor that term unless you go into imaginary numbers.

5. Nov 20, 2009

Staff: Mentor

That's what I thought you might be thinking.