Use the properties of logarithma to xpand the logarithmic function

In summary, to expand the logarithmic function ln[(x2+1)(x-1)], you can first use the property ln(a*b) = ln(a) + ln(b) to rewrite it as ln(x^2+1) + ln(x-1). However, you cannot simply rewrite ln(x^2+1) as ln(x^2)+ln(1) because you cannot factor out a term from x^2+1.
  • #1
Ki-nana18
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0

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
 
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  • #2
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
gamer_x_ said:
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
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
That's what I thought you might be thinking.
 

1. What are the basic properties of logarithms?

The basic properties of logarithms include the product rule, quotient rule, and power rule. The product rule states that the logarithm of a product is equal to the sum of the logarithms of each factor. The quotient rule states that the logarithm of a quotient is equal to the difference of the logarithms of the numerator and denominator. The power rule states that the logarithm of a power is equal to the product of the power and the logarithm of the base.

2. How do you use the product rule to expand a logarithmic function?

To use the product rule to expand a logarithmic function, first identify each factor in the product. Then, apply the product rule by taking the logarithm of each factor and adding them together. This will result in the expanded logarithmic function.

3. Can you explain the quotient rule for logarithms?

The quotient rule for logarithms states that the logarithm of a quotient is equal to the difference of the logarithms of the numerator and denominator. In other words, to expand a logarithmic function with a quotient, you can subtract the logarithm of the denominator from the logarithm of the numerator.

4. How do you expand a logarithmic function with a power using the power rule?

To expand a logarithmic function with a power using the power rule, simply multiply the power by the logarithm of the base. This will result in an expanded logarithmic function with the power as the coefficient.

5. Are there any other properties of logarithms that can be used to expand a logarithmic function?

Yes, there are a few other properties of logarithms that can be used to expand a logarithmic function. These include the change of base formula and the logarithm of a reciprocal rule. The change of base formula allows you to rewrite a logarithm with a different base, while the logarithm of a reciprocal rule states that the logarithm of a reciprocal is equal to the negative of the logarithm of the original number. These properties can be useful when expanding more complex logarithmic functions.

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