Why is lim x->infinity of 2^-x = 0?

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In summary, the limit of 2^-x approaches 0 as x approaches infinity because as the exponent decreases, the value of 2^-x also decreases, resulting in a limit of 0. This can be proven using the definition of a limit, and it has significance in various mathematical and scientific fields. The limit of 2^-x is always equal to 0 as x approaches infinity, and it cannot be equal to any other value.
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Homework Statement



Hey guys, just getting into the exponential functions and got stuck on something. Can someone please explain this for me?

Find lim x-->∞ (2^-x)

The answer is 0

Why? I don't quite understand.

I know that something like 2^-x would just be 1/2^x

?


Homework Equations





The Attempt at a Solution

 
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2^-x = 1/(2^x)

As x tends to infinity, what happens to the denominator, (2^x)?
 

1. Why does the limit of 2^-x approach 0 as x approaches infinity?

The limit of a function represents the value that the function approaches as its input approaches a certain value, in this case, infinity. As x gets larger and larger, the value of 2^-x gets closer and closer to 0 because the exponent, x, becomes increasingly negative. As the exponent decreases, the value of 2^-x decreases as well, resulting in a limit of 0.

2. Can you prove that lim x->infinity of 2^-x is equal to 0?

Yes, we can prove this using the definition of a limit. Let's define a function f(x) = 2^-x and set the limit as x approaches infinity. By definition, the limit is equal to L if for any value of ε (epsilon) greater than 0, there exists a value of x such that whenever x > x0, the absolute difference between f(x) and L is less than ε. In this case, we can choose any value of x0, and as x gets larger, the value of f(x) = 2^-x gets closer and closer to 0, satisfying the definition of a limit equal to 0.

3. What is the significance of lim x->infinity of 2^-x = 0 in mathematics?

This limit is significant because it shows that the exponential function 2^-x decreases rapidly as x approaches infinity. This concept is used in various mathematical and scientific fields, such as calculus, probability, and finance, to model situations where quantities decrease exponentially over time or distance. Understanding the behavior of exponential functions, including their limits, is crucial in these applications.

4. Is the limit of 2^-x always equal to 0 as x approaches infinity?

Yes, the limit of 2^-x is always equal to 0 as x approaches infinity. This is because 2^-x is an exponential function with a base less than 1, which means that it will always approach 0 as x gets larger. Even if the exponent is a large negative number, the value of 2^-x will still approach 0 as x approaches infinity.

5. Can the limit of 2^-x be equal to any other value besides 0 as x approaches infinity?

No, the limit of 2^-x can only be equal to 0 as x approaches infinity. This is because the behavior of exponential functions with a base less than 1 is such that they will always approach 0 as the input approaches infinity. Therefore, the limit of 2^-x will always be 0, regardless of the value of the exponent x.

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