Evaluating Limits with trig functions

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SUMMARY

The limit evaluation of lim x-->0 sin(pi/x) sqrt(x^3+x^2) reveals that as x approaches 0, sin(pi/x) oscillates between -1 and 1. This oscillation allows for the application of the Squeeze Theorem, leading to the conclusion that the limit is 0. The expression can be bounded by -sqrt(x^3+x^2) and sqrt(x^3+x^2), both of which approach 0 as x approaches 0. Understanding the behavior of sine functions and their limits is crucial for solving such problems.

PREREQUISITES
  • Understanding of the Squeeze Theorem in calculus
  • Familiarity with trigonometric identities, particularly fundamental identities
  • Knowledge of limits and continuity in calculus
  • Basic algebraic manipulation skills for simplifying expressions
NEXT STEPS
  • Review the Squeeze Theorem and its applications in limit evaluation
  • Study trigonometric identities and their implications in limit problems
  • Practice evaluating limits involving oscillating functions
  • Explore advanced limit techniques, including L'Hôpital's Rule
USEFUL FOR

Students studying calculus, particularly those focusing on limits and trigonometric functions, as well as educators seeking to enhance their teaching methods for limit evaluations.

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Homework Statement


lim x-->0 sin(pi/x) sqrt(x^3+x^2)

The Attempt at a Solution



I was having trouble evaluating the above limit. Do I start by isolating x? For some reason, when it comes to trig functions such as this, I'm not sure how to simplify it. Also, what material would I have to review for me to understand how to break down such trig functions? I'm aware of fundamental, quotient and reciprocal identities of trig functions but am not sure how to use that knowledge to solve these type of problems.
 
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As x goes to 0, sin(pi/x) oscillates but stays between -1 and 1. That is,
-\sqrt{x^3+ x^2}\le sin(\pi/x)\sqrt{x^3+ x^2}\le \sqrt{x^3+ x^2}
 
Use the fact that :

|sin(x)| ≤ 1 \forallx\niR

As in FOR ALL x you happen to plug into the sin function including whatever value gets spat out of pi/x.

hint hint ;)
 

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