Can the limit of a quotient of trig functions approach a specific value?

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SUMMARY

The limit of the quotient of sine and cosine functions, specifically lim x→∞ sin(ln(x))/cos(√x), does not converge to a specific value as both sine and cosine oscillate between -1 and 1. Applying L'Hôpital's rule requires careful consideration of its conditions, which may not be satisfied in this case. WolframAlpha indicates that the limit approaches both +∞ and -∞, reinforcing the conclusion that the limit does not exist. A transformation using y = √x simplifies the analysis but still necessitates a thorough review of L'Hôpital's rule's applicability.

PREREQUISITES
  • Understanding of limits in calculus
  • Familiarity with L'Hôpital's rule and its conditions
  • Knowledge of trigonometric functions and their properties
  • Basic logarithmic functions and their behavior
NEXT STEPS
  • Review the conditions for applying L'Hôpital's rule in depth
  • Explore the behavior of sin(ln(x)) and cos(√x) as x approaches infinity
  • Investigate transformations in limit problems, particularly using substitutions like y = √x
  • Utilize computational tools like WolframAlpha for limit evaluations and comparisons
USEFUL FOR

Students and educators in calculus, mathematicians exploring limits, and anyone seeking to deepen their understanding of trigonometric limits and L'Hôpital's rule.

Jonas
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Homework Statement
Can lim x-> infinity sin(ln(x)) /cos(sqrt(x)) be evaluated with L'Hôpitals rule?
Relevant Equations
lim x→∞ sin(ln(x))/cos(√x)
Hello.
Sin and cos separately oscillates between [-1,1] so the limit of each as x approach infinity does not exist.
But can a quotient of the two acutally approach a certain value?
lim x→∞ sin(ln(x))/cos(√x) has to be rewritten if L'hôp. is to be applied but i can't seem to find a way to rewrite it to get a meaningful answer. Ofc i tried wolframalpha who states that it approaches + and - infinity which made me even more confused since i would normally interpret that as the limit does not exist?
 
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The function isn't defined where the denominator is zero. And, in any case, if you analyse those points you'll see the problem.

It's simpler if you let ##y = \sqrt x## and take ##y \rightarrow \infty##.
 
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You should look at the specific conditions where L'Hopital's rule can be used and see if those conditions are met. I suggest that you carefully review the statement of L'Hopital's rule. If you find one condition that is not met, state that condition and show that it is not met.
 
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