Solving Homework Problems: Evaluating Limits of f(X) as X->0

In summary, the conversation discusses a misunderstanding about how to evaluate a certain type of homework problem involving limits. The speaker initially struggles with understanding how to evaluate the limit of f(X) as X approaches 0, but then realizes that f(X) must equal X for the limit to be 0. However, another person points out that this reasoning is incorrect, using the example of the limit of sin x/x as x approaches 0. They suggest using the product rule for limits to evaluate these types of problems.
  • #1
Lucy788
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hi I don't understand how to do one type of homework problem, here's an example of the type:
If limit of f(X)/X = 1 as X ->0 evaluate the limit f(X) as X->0
 
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  • #2
Lucy788 said:
hi I don't understand how to do one type of homework problem, here's an example of the type:
If limit of f(X)/X = 1 as X ->0 evaluate the limit f(X) as X->0
I realize now that f(X) must equal X and therefor the limit is 0
 
  • #3
Lucy788 said:
hi I don't understand how to do one type of homework problem, here's an example of the type:
If limit of f(X)/X = 1 as X ->0 evaluate the limit f(X) as X->0
Lucy788 said:
I realize now that f(X) must equal X and therefor the limit is 0
That's not a correct argument.

For example, ##\displaystyle \lim_{x\rightarrow 0} \frac{\sin x}{x}=1##, but clearly ##\sin x \neq x## (for ##x \neq 0##).

You could use the product rule for limits: ##\displaystyle \lim_{x\rightarrow 0} g(x)h(x)=(\lim_{x\rightarrow 0} g(x))(\lim_{x\rightarrow 0} h(x))## provided the limits exist.
Notice that ##f(x)=x\frac{f(x)}{x}##.
 
Last edited:

Related to Solving Homework Problems: Evaluating Limits of f(X) as X->0

1. What is meant by "evaluating limits of f(X) as X->0"?

The limit of a function at a certain point, in this case as X approaches 0, is the value that the function approaches as the input approaches that point. In other words, it is the value that the function is "heading towards" as the input gets closer and closer to 0.

2. Why is it important to evaluate limits of f(X) as X->0?

Evaluating limits helps us understand the behavior of a function near a particular point. In this case, evaluating the limit as X approaches 0 can tell us about the behavior of the function near the origin.

3. How do I solve for the limit of f(X) as X->0?

To solve for the limit of a function as X approaches 0, you can use algebraic techniques such as factoring and simplifying, or you can use a graphing calculator or online tool to visualize the behavior of the function near the origin.

4. Are there any special cases when evaluating limits of f(X) as X->0?

Yes, there are several special cases to consider. For example, if the function is undefined at 0, the limit may not exist. Additionally, if the function has a vertical asymptote at 0, the limit may approach positive or negative infinity.

5. How can evaluating limits of f(X) as X->0 be applied in real life?

Evaluating limits can be used in various fields such as physics, engineering, and economics to model and predict the behavior of systems and phenomena. For example, in physics, limits can be used to calculate instantaneous rates of change and determine the behavior of particles in motion.

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