How to prove that (n+1)/2^n is divergent

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In summary, a sequence is divergent when its terms do not approach a single finite value, but instead increase or decrease without bound. To prove that (n+1)/2^n is divergent, we can use the limit comparison test, the ratio test, or other tests such as the integral test, direct comparison test, or root test. A graph cannot be used to prove divergence, as mathematical tests and methods must be used.
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isukatphysics69
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Homework Statement


Prove that (n+1)!/2^n is divergent

Homework Equations

The Attempt at a Solution


i know that factorials grow faster than exponentials. But on an exam i would not know how to actually prove that this is divergent other than saying that the numerator is growing much faster than the denominator. i cannot find in my book where they prove this.
 
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i will try ratio test
 
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isukatphysics69 said:
i will try ratio test
This will work.
 
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1. What does it mean for a sequence to be divergent?

When a sequence is divergent, it means that the terms in the sequence do not approach a single finite value, but instead either increase or decrease without bound.

2. How can I prove that (n+1)/2^n is divergent?

One way to prove that (n+1)/2^n is divergent is by using the limit comparison test. We can compare this sequence to the sequence 1/2^n, which we know is divergent. By taking the limit as n approaches infinity of (n+1)/2^n divided by 1/2^n, we can see that the limit is equal to 2, which is not equal to 0. Therefore, (n+1)/2^n is also divergent.

3. Can I use the ratio test to prove that (n+1)/2^n is divergent?

Yes, the ratio test can also be used to prove that (n+1)/2^n is divergent. When applying the ratio test, we take the limit as n approaches infinity of the absolute value of (a_n+1)/(a_n). In this case, a_n = (n+1)/2^n. By simplifying the limit, we can see that it approaches infinity, indicating that the series is divergent.

4. Are there any other tests I can use to prove that (n+1)/2^n is divergent?

Yes, there are several other tests that can be used to prove that (n+1)/2^n is divergent. These include the integral test, the direct comparison test, and the root test. Each of these tests has its own criteria for determining divergence, but they all point to (n+1)/2^n being a divergent sequence.

5. Can I use a graph to prove that (n+1)/2^n is divergent?

No, a graph cannot be used to definitively prove that (n+1)/2^n is divergent. While a graph can give us a visual representation of the sequence, it cannot provide a mathematical proof. To prove divergence, we must use mathematical tests and methods to analyze the behavior of the sequence as n approaches infinity.

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