How do I solve the limit of tan^2(2x) / 3x^2 as x approaches 0?

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Homework Help Overview

The discussion revolves around evaluating the limit of the expression tan^2(2x) / 3x^2 as x approaches 0, which falls under the subject area of calculus, specifically limits and trigonometric functions.

Discussion Character

  • Exploratory, Assumption checking, Mathematical reasoning

Approaches and Questions Raised

  • Participants explore various approaches to simplify the limit, including the substitution of tan(2x) with sin(2x)/cos(2x) and questioning the validity of known limits such as lim (2x -> 0) tan(2x)/(2x) = 1.

Discussion Status

The discussion includes attempts to clarify the limit's evaluation and hints towards using known limits. Some participants express uncertainty about their starting points, while others provide guidance that may help in approaching the problem.

Contextual Notes

There is mention of a potential application of L'Hôpital's rule, as well as a specific limit result that participants are encouraged to consider. The original poster expresses a lack of progress, indicating possible constraints in their understanding or approach.

theCandyman
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I am completely lost on where to start, any help would be appreciated:

lim (x->0) tan^2(2x) / 3x^2

I do not have any work so far, but I'm trying to find a way to get rid of the x^2 in the denominator, which so far has been fruitless.
 
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Try replacing tan(2x) with sin(2x)/cos(2x). You probably know something about the limit of sin(x)/x as x->0.
 
theCandyman said:
I am completely lost on where to start, any help would be appreciated:

lim (x->0) tan^2(2x) / 3x^2

I do not have any work so far, but I'm trying to find a way to get rid of the x^2 in the denominator, which so far has been fruitless.

This limit works fine without the aid of Mr.L'Ho^pital.
Are u 100% convinced that:
[tex]\lim_{2x \rightarrow 0} \frac{\tan{2x}}{2x} =1[/tex]
??

If so,u'll be able to apply the formula above properly and get the result.

One more hint:
[tex]\lim_{x \rightarrow 0} \frac{\tan^{2} 2x}{3x^2} = \frac{4}{3} <br /> (\lim_{2x \rightarrow 0} \frac{\tan{2x}}{2x})^{2}[/tex]

I hope you can take it from there.
 
Thank you both, I have my answer now.
 

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