What is the Limit of a Function as x Approaches 0?

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SUMMARY

The limit of a function as x approaches 0 can be effectively computed using Taylor series expansions for trigonometric functions. Specifically, expanding cos(2x) and sin(x) allows for the cancellation of terms, facilitating the calculation of the limit. While l'Hopital's rule is a common approach, it may require repeated differentiation without yielding a straightforward answer. Utilizing Taylor series is a more efficient method for solving these types of limit problems.

PREREQUISITES
  • Understanding of Taylor series expansions for trigonometric functions
  • Familiarity with l'Hopital's rule for limits
  • Basic knowledge of calculus, particularly limits
  • Ability to manipulate algebraic expressions for simplification
NEXT STEPS
  • Learn how to derive Taylor series for sin(x) and cos(x)
  • Practice applying l'Hopital's rule in various limit scenarios
  • Explore advanced limit techniques, including epsilon-delta definitions
  • Investigate other functions suitable for Taylor series expansion
USEFUL FOR

Students studying calculus, particularly those tackling limit problems, as well as educators seeking effective teaching methods for explaining limits and series expansions.

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Homework Statement



http://i45.tinypic.com/20rsnis.jpg

Homework Equations



Compute the lim

The Attempt at a Solution


I tried using l'Hopital's rule but I have to keep finding the derivative and it doesn't yield an answer. I have to use taylor series for the trig functions, but don't know how this will work
 
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Go ahead, try it. Expand cos(2x) and sin(x) in a taylor series. See which terms cancel. If you don't know the expansion of cos and sin, they are easy to look up.
 
http://en.wikipedia.org/wiki/Taylor_series

a good rule of thumb is to turn sin and cosine and even e into their taylor series whenever doing limit problems. then subtract whatever you can. and factor out as many x terms as you need to make the top and bottom non zero. and then calculate the limit.
 

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