Is Finding a Common Denominator Necessary for Evaluating This Limit?

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In summary, the conversation discusses evaluating a limit and the use of itex for formatting equations. The limit in question is \lim_{x\to 0}\left(\frac{1}{sin^2x}+\frac{1}{x^2}\right) and it is suggested to find a common denominator. The final response acknowledges the post without calculus knowledge and explains why a common denominator is not needed in this case.
  • #1
Lizwi
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How do I evaluate this limit I have no Idea, I'm sorry for not showing my work please!

limx[itex]\rightarrow[/itex]0 [itex]\frac{1}{sin2x}[/itex] +[itex]\frac{1}{x2}[/itex]
 
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  • #2


Doesn't it go to infinity?
 
  • #3


What happens when you have...

[itex]lim_{x\to 0^+} \frac {1}{x}[/itex]

That is a basic limit, answering that should lead you to what you want.
 
  • #4


When using itex, you wouldn't use the other tags that the board uses such as for superscripts; you would use ^ to make exponents.

Could you have meant this limit with subtraction instead?
[itex]\lim_{x\to 0}\frac{1}{\sin^2x} - \frac{1}{x^2}[/itex]
 
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  • #5


Lizwi said:
How do I evaluate this limit I have no Idea, I'm sorry for not showing my work please!

[tex]\lim_{x\to 0}\left(\frac{1}{sin^2x}+\frac{1}{x^2}\right)[/tex]


I already edited your post above. Now read the other posts.

DonAntonio
 
  • #6


I have not taken calc yet, but would he need to find a common denominator?
 
  • #7


ME_student said:
I have not taken calc yet, but would he need to find a common denominator?


Kudos for the courage to post without having yet studied calculus..:) In this case it isn't needed to find

common denominator as: (1) both parts of the expression are positive, (2) it's a sum and (3) both tend to [itex]\infty[/itex] as [itex]x\to 0[/itex]

DonAntonio
 

FAQ: Is Finding a Common Denominator Necessary for Evaluating This Limit?

What is the process for evaluating a limit?

To evaluate a limit, you must first plug in the given value to the function. Then, simplify the expression as much as possible. If you get an indeterminate form, you may need to use algebraic manipulation or one of the limit laws to solve. If the limit still cannot be determined, you may need to use more advanced techniques like L'Hopital's rule or Taylor series.

2. How do I know if a limit exists?

A limit exists if the left-hand limit and the right-hand limit are equal. This means that the function approaches the same value from both sides of the given value. If these two limits are not equal, then the limit does not exist.

3. Can I use a calculator to evaluate a limit?

It depends on the limit. If the limit can be evaluated algebraically, then you can use a calculator to help with computations. However, if the limit involves more complex techniques like L'Hopital's rule, then a calculator may not be accurate.

4. What are some common mistakes to avoid when evaluating limits?

Some common mistakes to avoid are forgetting to check for indeterminate forms, not simplifying the expression enough, and using incorrect limit laws. It is also important to check that the given value is within the domain of the function.

5. Is there a shortcut for evaluating limits?

There is no one-size-fits-all shortcut for evaluating limits. However, there are certain techniques and rules that can help simplify the process, such as using the limit laws or recognizing common functions and their limit values. It is important to understand the concept of limits and practice solving various types of limits to become more efficient at evaluating them.

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