Infinite Series Doubt: Last Step Explained

Click For Summary
SUMMARY

The discussion centers on the concept of finite geometric series and its application in understanding infinite series. The formula for the sum of a finite geometric series, \sum_{k=1}^{n}r^k = r\frac{1-r^n}{1-r}, is clarified as representing only the first n terms, making it a finite series. The transition to an infinite series occurs by taking the limit of the finite sum s_n as n→∞. This distinction is crucial for grasping the behavior of series as they extend indefinitely.

PREREQUISITES
  • Understanding of geometric series
  • Familiarity with limits in calculus
  • Basic knowledge of series convergence
  • Ability to manipulate algebraic expressions
NEXT STEPS
  • Study the properties of geometric series in detail
  • Learn about limits and their applications in calculus
  • Explore convergence tests for infinite series
  • Practice problems involving the transition from finite to infinite series
USEFUL FOR

Students of mathematics, particularly those studying calculus and series, educators explaining series concepts, and anyone seeking to strengthen their understanding of geometric series and limits.

RoughRoad
Messages
63
Reaction score
0
On the provided attachment, I have problem understanding the last step of the 1st sum of that page. Can anyone explain to me what is being done after the second-last step?
 

Attachments

Physics news on Phys.org
They're using the formula for the sum of a finite geometric series:
\sum_{k=1}^{n}r^k = r\frac{1-r^n}{1-r}
 
How is it a finite series? Aren't the term going till infinity? Sorry but I am actually a litle weak on my basics.
 
The term s_n is the sum of just the first n terms, which is a finite series. The value of the infinite series is obtained by taking the limit of s_n as n→∞.
 
Thanks! :-)
 

Similar threads

  • · Replies 7 ·
Replies
7
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 3 ·
Replies
3
Views
3K
  • · Replies 20 ·
Replies
20
Views
3K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 2 ·
Replies
2
Views
1K
  • · Replies 2 ·
Replies
2
Views
2K