Squeeze Theorem Math Example 4

Follow the full solution, then compare it with the other examples linked below.

Example 4

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Show that limโกnโ†’โˆžsinโกnn=0\displaystyle\lim_{n\to\infty} \frac{\sin n}{n} = 0.

Solution

  1. 1
    โˆ’1โ‰คsinโกnโ‰ค1-1 \leq \sin n \leq 1 for all integers nn.
  2. 2
    Dividing by n>0n > 0: โˆ’1nโ‰คsinโกnnโ‰ค1n-\frac{1}{n} \leq \frac{\sin n}{n} \leq \frac{1}{n}.
  3. 3
    limโกnโ†’โˆž1n=0\lim_{n\to\infty} \frac{1}{n} = 0, so by the squeeze theorem, limโกnโ†’โˆžsinโกnn=0\lim_{n\to\infty}\frac{\sin n}{n} = 0.

Answer

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The squeeze theorem works for sequences too. Bounding sinโกn\sin n between -1 and 1, then dividing by a growing nn, forces the middle term to 0.

About Squeeze Theorem

If g(x)โ‰คf(x)โ‰คh(x)g(x) \leq f(x) \leq h(x) near x=ax = a, and limโกxโ†’ag(x)=limโกxโ†’ah(x)=L\lim_{x \to a} g(x) = \lim_{x \to a} h(x) = L, then limโกxโ†’af(x)=L\lim_{x \to a} f(x) = L.

Learn more about Squeeze Theorem โ†’

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