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Use the properties of logarithma to xpand the logarithmic function

  • Thread starter Ki-nana18
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  • #1
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Homework Statement


Use the properties of logarithma to xpand the logarithmic function ln[(x2+1)(x-1)]


Homework Equations





The Attempt at a Solution


[ln x2+ln 1]+[ln x-ln 1]
2 ln x+ln x
 

Answers and Replies

  • #2
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the first step makes sense: [tex]ln[(x^2+1)(x-1)]=ln(x^2+1)+ln(x-1)[/tex]

but then you continued: [tex]ln(x^2+1)=ln(x^2)+ln(1)[/tex]

You can't do that, but you can do something else to the [tex]x^2+1[/tex]...
 
  • #3
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the first step makes sense: [tex]ln[(x^2+1)(x-1)]=ln(x^2+1)+ln(x-1)[/tex]

but then you continued: [tex]ln(x^2+1)=ln(x^2)+ln(1)[/tex]

You can't do that, but you can do something else to the [tex]x^2+1[/tex]...
Is the something else you're thinking about factoring x^2 + 1?
 
  • #4
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I just realized I was stupidly thinking of [tex]x^2-1[/tex] not [tex]x^2+1[/tex]. You can't really factor that term unless you go into imaginary numbers.
 
  • #5
33,090
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That's what I thought you might be thinking.
 

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