Can rational functions inside logarithms have removable discontinuities?

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SUMMARY

The discussion centers on the nature of removable discontinuities in the function f(x) = ln[(x-x^2)/x]. It is established that x = 0 is indeed a removable discontinuity due to the rational function inside the logarithm. The reasoning is based on the ability to cancel factors in rational functions, similar to the example provided with (x+2)/[(x+2)(x+3)], which has a removable discontinuity at x = -2. The key takeaway is that understanding the properties of logarithmic functions and rational expressions is essential in identifying removable discontinuities.

PREREQUISITES
  • Understanding of logarithmic functions, specifically natural logarithms.
  • Knowledge of rational functions and their properties.
  • Familiarity with the concept of removable discontinuities in calculus.
  • Ability to manipulate algebraic expressions, including factoring and canceling terms.
NEXT STEPS
  • Study the properties of logarithmic functions, focusing on their domains and discontinuities.
  • Learn about the concept of limits and continuity in calculus.
  • Explore examples of rational functions with removable discontinuities and their graphical representations.
  • Investigate the implications of discontinuities in real-world applications, such as in physics or engineering.
USEFUL FOR

Students studying calculus, particularly those focusing on limits and continuity, as well as educators teaching these concepts. This discussion is also beneficial for anyone looking to deepen their understanding of logarithmic functions and their behavior in relation to rational expressions.

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Homework Statement



f(x) = ln[(x-x^2)/x]

Is x = 0 a removable discontinuity?

Homework Equations



Removable discontinuities are points that can be filled in on a graph to make it continuous.

The Attempt at a Solution



Is it? I know that with rational functions, canceling out factors can result in removable discontinuities. For example, the function (x+2)/[(x+2)(x+3)] has a removable discontinuity at x = -2 since the factor (x+2) can be canceled out.

What about rational functions inside logarithms?
 
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Qube said:

Homework Statement



f(x) = ln[(x-x^2)/x]

Is x = 0 a removable discontinuity?

Homework Equations



Removable discontinuities are points that can be filled in on a graph to make it continuous.

The Attempt at a Solution



Is it? I know that with rational functions, canceling out factors can result in removable discontinuities. For example, the function (x+2)/[(x+2)(x+3)] has a removable discontinuity at x = -2 since the factor (x+2) can be canceled out.

What about rational functions inside logarithms?

What do you think? If you think the answer is NO, why would you think that? Ditto if you think the answer is YES.
 
@Qube: you appear to have answered your own question without realizing it.
Probably you need to focus on what it means for a discontinuity to be "removeable".

Removable discontinuities are points that can be filled in on a graph to make it continuous.
... not quite right is it? If you plotted y=(x+2)/[(x+2)(x+3)] would there be a discontinuity on the graph?
 

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