Solve Converging Sequence: 1 + 1/8 + 1/27 + 1/64...

In summary, the conversation discusses how to solve the series 1 + 1/8 + 1/27 + 1/64... and its convergence. The conversation mentions using the integral test to determine convergence and finding the sum using the Riemann zeta function or Apéry's constant. The person asking for help is a high school student and is ultimately looking for a decimal approximation of the sum.
  • #1
Hockeystar
64
0

Homework Statement


Solve 1 + 1/8 + 1/27 + 1/64...


Homework Equations


Stuck here.


The Attempt at a Solution



I know the series is infinitetly adding 1/n^3. I know it should converge. How do I solve as lim x--> infinity. Teacher never gave us any info, he just said use number sense.
 
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  • #2
Hockeystar said:

Homework Statement


Solve 1 + 1/8 + 1/27 + 1/64...


Homework Equations


Stuck here.


The Attempt at a Solution



I know the series is infinitetly adding 1/n^3. I know it should converge. How do I solve as lim x--> infinity. Teacher never gave us any info, he just said use number sense.
What exactly does "solve" mean? Are you supposed to find the sum of this series, or do you only need to say that it converges or diverges?

If it's the latter, do you know any tests you can use to determine convergence or divergence?
 
  • #3
try integral test
 
  • #4
My teacher wanted to know the sum. Integral test is as n--> infinity, 1/x^6 is finite (0). Therefore the series converges. How do I find the sum then? Sohuld I just try trial and error and see what it seems to approach?
 
  • #5
I don't think there's a good closed form for that sum other than ζ(3), the Riemann zeta function.
 
  • #6
I could do 1/n^2 infinite sum is (pi^2)/6 and then multiply by infinite 1/n but that series diverges. Found solution on wikipedia. http://en.wikipedia.org/wiki/Apéry's_constant

I think my teacher was just looking for a decimal approx (only H.S calc. class) Thanks for the help everyone.
 

FAQ: Solve Converging Sequence: 1 + 1/8 + 1/27 + 1/64...

What is a converging sequence?

A converging sequence is a sequence of numbers that approaches a specific limit as the number of terms in the sequence increases. In other words, the terms in the sequence get closer and closer to a certain value as the sequence goes on.

How do you solve a converging sequence?

To solve a converging sequence, you can use the formula for the sum of an infinite geometric series, which is Sn = a / (1-r), where a is the first term and r is the common ratio. Alternatively, you can find the limit of the sequence by taking the limit as n approaches infinity of the nth term in the sequence.

What is the common ratio in this sequence?

The common ratio in this sequence is 1/8. This means that each term in the sequence is multiplied by 1/8 to get the next term.

What is the limit of this sequence?

The limit of this sequence is 1. As the number of terms in the sequence approaches infinity, the terms get closer and closer to 1, but never quite reach it.

How can converging sequences be applied in real life?

Converging sequences can be used in various real-life applications, such as in finance and economics to calculate compound interest or in physics to model exponential decay. They can also be used in computer algorithms and data analysis to estimate and predict future values based on past trends.

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