Limits at infinity of trigometric function

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SUMMARY

The limit of the function as x approaches pi, specifically lim (x→pi) sin(x-pi)/(x-pi), can be evaluated using the substitution u = x - pi. This transforms the limit into lim (u→0) sin(u)/u, which is a well-known limit that equals 1. The discussion highlights the importance of recognizing familiar limits and suggests the use of the squeeze theorem as an alternative method for solving similar problems.

PREREQUISITES
  • Understanding of trigonometric identities, specifically sin(a-b) = sinA cosB - cosA sinB.
  • Familiarity with limits in calculus, particularly limits involving trigonometric functions.
  • Knowledge of the squeeze theorem and its application in limit evaluation.
  • Basic substitution techniques in calculus for simplifying limits.
NEXT STEPS
  • Study the derivation and proof of lim (u→0) sin(u)/u = 1.
  • Explore the application of the squeeze theorem in various limit problems.
  • Practice solving limits involving trigonometric functions using different techniques.
  • Review advanced trigonometric identities and their applications in calculus.
USEFUL FOR

Students studying calculus, particularly those focusing on limits and trigonometric functions, as well as educators looking for effective teaching strategies for these concepts.

Willian93
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Homework Statement




lim (x→pi)〖sin(x-pi)/(x-pi)〗

Homework Equations



i don't know if we should use trig identity

sin(a-b)= sinA cos B- CosA sin B

The Attempt at a Solution


i use identities to solve that, i did not get the answer. i tried to multiply by conjugate, did not work also.
 
Last edited:
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Think about the squeeze theorem.
 
You could use a substitution, u = x - \pi, and that limit should be familiar.
 
Question: A clock's minute hand has length 4 and its hour hand has length 3. What is the distance between the tips at the moment when it is increasing most rapidly?(Putnam Exam Question) Answer: Making assumption that both the hands moves at constant angular velocities, the answer is ## \sqrt{7} .## But don't you think this assumption is somewhat doubtful and wrong?

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