Limits: Finding the Value of (x - Sinx) / x^3

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To find the limit of (x - Sinx) / x^3 as x approaches 0, L'Hôpital's Rule is suggested since it results in an indeterminate form of 0/0. By applying L'Hôpital's Rule, one differentiates the numerator and denominator until a determinate form is achieved. Alternatively, using the Maclaurin series expansion for Sinx can also lead to the solution. The expected limit value is 1/6, which can be derived through either method. Understanding these techniques is essential for solving similar limit problems.
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Homework Statement


lim (x->0) of (x - Sinx) / x^3


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The Attempt at a Solution


I would like to know the proper route for analyzing that question... the text is saying i should end up with 1/6 ...however I'm not sure how they arrived at that answer ...
 
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Are you familiar with l'hopitale's rule?

if lim (x->0) a/b = 0/0 or infinity/infitity then lim (x->0) a/b = lim (x->0) a'/b'
 
not familiar with that yet ...
 
Another approach is to replace sin x by a few terms of its Maclaurin series, but if you don't know L'Hopital's Rule, you probably don't know anything about series yet, either. Short of those two techniques, I can't think of anything else that would work for you.
 
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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