Summation of a Logarithmic Series

Click For Summary
The series log(3/2) + log(4/3) + log(5/4) + ... + log(200/199) simplifies to log(3/2 * 4/3 * 5/4 * ... * 200/199). The key observation is that most terms cancel out, leaving only the first numerator (200) and the last denominator (2). This results in the expression log(200/2), which simplifies further to log(100). Recognizing the cancellation pattern is crucial for solving the series efficiently. Understanding this concept can enhance problem-solving skills in logarithmic series.
S.R
Messages
81
Reaction score
0

Homework Statement


What is the sum of the following series?

log(3/2)+log(4/3)+log(5/4)+...log(200/199).

Where log(x) is log base 10 of x.

Homework Equations





The Attempt at a Solution


Evidently, the previous form equals:

log(3/2*4/3*5/4*...200/199)

I'm missing something - no patterns are evident to me other than the denominator and numerator of the subsequent terms cancel out.

Any guidance would be appreciated.
 
Physics news on Phys.org
S.R said:
I'm missing something - no patterns are evident to me other than the denominator and numerator of the subsequent terms cancel out.

And that's important! What are you left with after cancelling *everything* that can be cancelled?
 
log(\frac{3}{2}*\frac{4}{3}*\frac{5}{4}*\frac{6}{5}...*\frac{200}{199})

Do you see in what pattern the terms cancel and which terms are left? :wink:
 
Intuitively, yes - would it be correct in saying that all terms cancel other than 1/2 and 200/1, leaving 200/2?
 
S.R said:
Intuitively no - however, would it be correct in saying that all terms cancel other than 1/2 and 200/1, leaving 200/2?
Yes, that would be correct, and you didn't find it intuitive even though you spotted the pattern?
 
S.R said:
Intuitively no - however, would it be correct in saying that all terms cancel other than 1/2 and 200/1, leaving 200/2?

Yes, only 1/2 and 200/1 remains. 3 cancels 1/3, 4 cancels 1/4, 5 cancels 1/5 but there's no one to cancel 200 and 1/2.
 
Quickly edited after rereading :frown:. I'm not sure why I didn't recognize that pattern before.
 

Similar threads

  • · Replies 17 ·
Replies
17
Views
2K
Replies
8
Views
2K
Replies
10
Views
2K
Replies
7
Views
2K
  • · Replies 10 ·
Replies
10
Views
3K
  • · Replies 3 ·
Replies
3
Views
2K
Replies
38
Views
6K
  • · Replies 12 ·
Replies
12
Views
2K
  • · Replies 5 ·
Replies
5
Views
3K
  • · Replies 7 ·
Replies
7
Views
2K