Take the 2-minute tour ×
Mathematics Stack Exchange is a question and answer site for people studying math at any level and professionals in related fields. It's 100% free, no registration required.

Wolfram understand this expression , but i need to do the limit when n tends to infinity of that expression .

As you can see in the wolfram web itself, in the last link it fails to understand the query.

How can i do that?

share|improve this question
1  
At the bottom, there is an "expanded form" of that expression. You can directly read the limit off that. –  Daniel Fischer Jul 3 '13 at 18:19
    
Do you want to make WolframAlpha understand it or you understand it? Which one is your main goal? The limit can be computed by hand. –  ABC Jul 3 '13 at 18:19
1  
This question is fully un- selfcontained. –  Did Jul 3 '13 at 19:09

1 Answer 1

up vote 4 down vote accepted

As suggested in the comment, at the very bottom of the page (first link), you'll see "Expanded form". If you merely "click" on the expression, the page will open to this page, where you'll find the limit of the expression stated explicitly:

Here's the limit (scroll down on the linked page to see it):

$$\lim_{n\to\pm\infty}\dfrac{4+24n+26n^2}{2n^2}=\dfrac{26}{3}\approx8.66667$$

Note that once you know the "expanded form" (or closed form) of the sum:

$$S(n) = \frac{4 + 24n + 26n^2}{3n^2},$$

Finding $\lim\limits_{n \to \infty} S(n)$ is fairly straightforward: We can see this limit more readily if we simply divide the numerator and denominator by $n^2:$

$$\lim_{n \to \infty}S(n) = \large \lim_{n \to \infty}\frac{\frac{4}{n^2} + \frac{24}{n} + 26}{3} = \frac {26}{3}$$

share|improve this answer
    
two answers ;-) =1 –  Amzoti Jul 4 '13 at 0:38

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.