Summation of a Logarithmic Series

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Homework Help Overview

The problem involves finding the sum of a logarithmic series defined as log(3/2) + log(4/3) + log(5/4) + ... + log(200/199), where log(x) refers to the logarithm base 10 of x.

Discussion Character

  • Exploratory, Assumption checking

Approaches and Questions Raised

  • Participants discuss the cancellation of terms in the series and explore the resulting expression after simplification. There is a focus on identifying which terms remain after cancellation.

Discussion Status

Some participants have offered guidance on recognizing patterns in the series, while others are questioning their understanding of the cancellation process. Multiple interpretations of the cancellation outcome are being explored, but there is no explicit consensus on the final result.

Contextual Notes

Participants express uncertainty about the patterns in the series and the implications of the cancellation, indicating a need for further clarification on the assumptions involved in the problem.

S.R
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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.
 
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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.
 

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