Does the following limit converge?
x → 0 lim sin x x 2 sin x 1
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x → 0 lim s i n x x 2 s i n ( 1 / x ) = x → 0 lim s i n x x × x → 0 lim x s i n ( 1 / x ) = 1 × x → 0 lim x s i n ( 1 / x )
As x → 0 then s i n ( 1 / x ) → s i n ( ∞ ) which will oscillates between [ − 1 , 1 ] .So this will be finite.Finite value multiplied with zero equals to zero.
So, the limit will be zero.
The last line could be clarified. Saying that "this will be finite" is meaningless because the limit of sin ( 1 / x ) does not exist, so it's unclear what you mean by sin ∞ .
You are actually using the squeeze theorem , that ∣ x sin x ∣ ≤ ∣ x ∣ and hence the limit is 0.
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But limit x s i n ( 1 / x ) exists
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Ah. Let me edit my comment to clarify.
Note: If you use
\sin
for the trigonometric function, that would make it easier to read.
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@Calvin Lin – So, I can edit my solution by writing squeeze theorem
sin(1/x)/(1/x)=xsin(1/x)=??!
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That is correct (with slight assumptions about the brackets).
Note that x 1 1 = x .
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x → 0 lim sin x x 2 sin x 1 = x → 0 lim sin x 1 ⋅ sin x x 2
We note that − 1 ≤ sin x 1 ≤ 1 is bounded and x → 0 lim sin x x 2 = 0 by L’Hôpital's rule , therefore, x → 0 lim sin x x 2 sin x 1 = 0