What Happens to ln[(x+2)/(x-1)] as x Approaches -2 from the Left?

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Homework Help Overview

The discussion revolves around the limit of the natural logarithm function ln[(x+2)/(x-1)] as x approaches -2 from the left. Participants are exploring the behavior of the function near this point, particularly focusing on the values of the numerator and denominator as x approaches -2.

Discussion Character

  • Exploratory, Assumption checking, Conceptual clarification

Approaches and Questions Raised

  • Participants are examining the limits of the numerator and denominator separately as x approaches -2 from the left. Questions are raised about the implications of these limits on the overall function and the behavior of the natural logarithm of the resulting ratio.

Discussion Status

There is an ongoing exploration of the limits involved, with some participants suggesting that the limit may approach negative infinity. Others are questioning the implications of the signs of the numerator and denominator on the limit of the logarithmic function.

Contextual Notes

Participants are considering the behavior of the function as x approaches -2, noting that the numerator approaches 0 while the denominator approaches a negative value. This context raises questions about the overall limit and the properties of logarithmic functions near these critical points.

gillgill
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i have done part of the work
but i got stuck here

what is
lim f(x) = lim ln [(x + 2)/(x - 1)] =?
x→-2- x→-2-

how do u solve for this?
 
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What is:
[tex]\lim_{x \rightarrow -2 ^ -} \frac{x + 2}{x - 1}[/tex]? Note that the numerator tends to 0, while the denominator tends to -3.
Then what can you say about:
[tex]\lim_{x \rightarrow 0 ^ +} \ln x[/tex]?
Viet Dao,
 
that would be -infinity??

how about
lim f(x) = lim ln [(x + 2)/(x - 1)] =?
x→-2+ x→-2+
 
Obviously, the numerator and denominator will separately approach the same values, so the ratio will also approach the same value. However, notice that in this case, the numerator will always be positive while the denominator will be negative. What does that tell you about the ratio? And what happens when you take the natural log of such a quantity? So, what can you say about the function when you try to take this limit?
 

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