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Limits of Trigonometric Functions. !

  • Thread starter gabyoh23
  • Start date
Limits of Trigonometric Functions. URGENT!

1. The problem statement, all variables and given/known data
Evaluate stackrel{lim}{x [tex]\rightarrow[/tex]0}[/tex] [sin(\frac{2e}{x3}) \bullet (arctanx)]


2. Relevant equations
All I know is that the equation stackrel{lim}{x [tex]\rightarrow[/tex]0}[/tex] [tex]\frac{sin x}{x}[/tex] = 1 might be helpful, but I'm not sure how to apply it to this particular problem.


3. The attempt at a solution
I talked to a friend of mine who's in Calc III, and she said that the whole limit would be equal to 0 since arctan(0) = 0, and sin[tex]\frac{2e}{x3}[/tex] is undefined, and the zero beats out the undefined value. This might be right, but how would I show that mathematically?

All help is greatly appreciated as I'm kind of in a crunch here :)
 
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Re: Limits of Trigonometric Functions. URGENT!

1. The problem statement, all variables and given/known data
Evaluate stackrel{lim}{x [tex]\rightarrow[/tex]0}[/tex] [sin(\frac{2e}{x3}) \bullet (arctanx)]


2. Relevant equations
All I know is that the equation stackrel{lim}{x [tex]\rightarrow[/tex]0}[/tex] [tex]\frac{sin x}{x}[/tex] = 1 might be helpful, but I'm not sure how to apply it to this particular problem.


3. The attempt at a solution
I talked to a friend of mine who's in Calc III, and she said that the whole limit would be equal to 0 since arctan(0) = 0, and sin[tex]\frac{2e}{x3}[/tex] is undefined, and the zero beats out the undefined value. This might be right, but how would I show that mathematically?

All help is greatly appreciated as I'm kind of in a crunch here :)
Here's your corrected limit expression.

Evaluate [tex]lim_{x \rightarrow 0} sin(\frac{2e}{x^3}) arctanx[/tex]

Your friend is leading you astray. It's not necessarily true that an expression tending to zero "beats out" an undefined value. What is true is that -1 <= sin(u) <= 1 for all real values of u.
 
Re: Limits of Trigonometric Functions. URGENT!

Thanks for correcting my formatting. I was in a rush, and I accidentally hit the "submit post" button before previewing it.

Thanks for the input!!
 

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