Analysis problem using the Lagrange Remainder Theorem

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The discussion focuses on proving the inequality involving the sine function and the Lagrange Remainder Theorem. The problem requires demonstrating that the absolute difference between sin(x+h) and the linear approximation sin(x) + hcos(x) is bounded by h²/2. Participants suggest using the Taylor polynomial of sine centered around x to facilitate the proof. There is uncertainty about how to derive the appropriate Taylor polynomial for comparison. The conversation emphasizes the importance of correctly applying the theorem to establish the desired inequality.
shan1732
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Homework Statement


Prove that for every pair of numbers x and h, \left|sin\left(x+h\right)-\left(sinx+hcosx\right)\right|\leq\frac{h^{2}}{2}


The Attempt at a Solution


Let f(x)= \left|sin\left(x+h\right)-\left(sinx-hcosx\right)\right|?
and then to center the taylor polynomial around 0 let h=0? I'm not sure how to get the taylor polynomial for this so that it can be compared to \frac{h^{2}}{2}
 
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Hi shan1732! :smile:

Try to calculate the Taylor polynomial of the sine around x.
 
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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