How can the Squeeze/Sandwich theorem be used to solve this limit problem?

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In summary, the Squeeze/Sandwich theorem can be used to show that the limit of the given expression as x approaches 1 is 0. This is done by splitting the expression into two separate limits and using the fact that sin(1/(1-x)) is always between -1 and 1. The limit of sin(1/(1-x)) as x approaches 1 does not exist, but the amplitude of its oscillations decreases as x approaches infinity.
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skateza
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Homework Statement


Use the Squeeze/Sandwich theorem to show the

[tex]limx->1 [(x-1)^{2}sin(\frac{1}{1-x})]=0[/tex]


Thats the lim as x approaches 1 for the whole square bracket

The Attempt at a Solution


i split it up into the two separate limits, but I'm kinda lost on how the sandwhich theorem works, my professor said something along the lines of sin1/1-x has to be between 1 and -1 because all sin are, than he change that to an x and found the limit as x approached zero and the two limits worked out, but this limit has x approaching 1 so I'm stuck.
 
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  • #2
If we let L be the form you are taking the limit of, then -(x-1)^2<=L<=+(x-1)^2, since the sin is always between -1 and +1, right? What are the outside limits?
 
  • #3
ok i solved it, it's 0... but i kinda just put what the data should be to obtain zero, how do u find the limit as x approaces 1 for sin(1/(1-x)), how can u tell what the sin of infinity is?
 
  • #4
It oscillates between -1 and 1. It doesn't have a limit. L oscillates too, but the amplitude of the oscillations get smaller and smaller as it approaches infinity.
 

FAQ: How can the Squeeze/Sandwich theorem be used to solve this limit problem?

What is the Squeeze/Sandwich Theorem?

The Squeeze/Sandwich Theorem, also known as the Squeeze/Sandwich Rule or the Pinching Theorem, is a mathematical theorem used to evaluate the limit of a function. It states that if two functions, g(x) and h(x), are both approaching the same limit as x approaches a particular value, and if a third function, f(x), is always between those two functions, then f(x) also approaches the same limit.

Why is the Squeeze/Sandwich Theorem useful?

The Squeeze/Sandwich Theorem is useful because it provides a method for evaluating limits of functions that may otherwise be difficult to calculate. It also allows us to prove the existence of limits by showing that two functions are approaching the same limit.

Can the Squeeze/Sandwich Theorem be used for all functions?

No, the Squeeze/Sandwich Theorem can only be used for functions that satisfy the sandwich condition. This means that the two functions, g(x) and h(x), must approach the same limit as x approaches a particular value, and f(x) must always be between these two functions. If this condition is not met, then the theorem cannot be applied.

How is the Squeeze/Sandwich Theorem different from other limit theorems?

The Squeeze/Sandwich Theorem is unique in that it does not require the function in question to be defined at the point where the limit is being evaluated. It only requires that the function approaches a particular limit as x approaches a value. Other limit theorems, such as the Intermediate Value Theorem, have stricter requirements and may not be applicable in all cases.

How is the Squeeze/Sandwich Theorem used in real-world applications?

The Squeeze/Sandwich Theorem can be used in a variety of real-world applications, such as in engineering, physics, and economics, to evaluate limits and prove the existence of limits. It can also be used to analyze the convergence and divergence of infinite series and to solve problems involving rates of change.

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