What is the limit of (2n+1)/(3n+7) as n approaches infinity?

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The limit of (2n+1)/(3n+7) as n approaches infinity is 2/3. To prove this, one can rewrite the expression as (2n(1 + 1/2n))/(3n(1 + 7/3n)). As n increases, the terms 1/2n and 7/3n approach zero, simplifying the expression to 2/3. While this method effectively finds the limit, it does not adhere strictly to the formal definition of limits. A rigorous proof from the definition would require demonstrating that for any ε > 0, there exists an N such that for all n > N, the absolute difference between the limit and the function is less than ε.
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let an = \frac{(2n+1)}{(3n+7)}. Prove direct from definition that an\rightarrow2/3.

Any help would be appreciated.
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ok … first step in a question like this is …

what is the definition of the statement "lim((2n+ 1)/(3n+7)) = 2/3"? :smile:
 
Here's an idea... as long as n isn't zero, the following two things are the same:

(2n+1)/(3n+7) = [(2n)(1+1/2n)]/[(3n)(1+7/3n)]

What happens as the n's get bigger and bigger to the terms 1/2n and 7/3n?
 
AUMathTutor said:
Here's an idea... as long as n isn't zero, the following two things are the same:

(2n+1)/(3n+7) = [(2n)(1+1/2n)]/[(3n)(1+7/3n)]

What happens as the n's get bigger and bigger to the terms 1/2n and 7/3n?
That's the simplest way of finding the limit but it doesn't "prove from the definition".
 
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