Very simple log problem - I'm missing something.

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Discussion Overview

The discussion revolves around a logarithmic problem involving the calculation of logarithms and their bases. Participants explore the discrepancies in results obtained using calculators versus those presented in an older textbook, focusing on the interpretation of logarithmic bases and the methods used for calculations.

Discussion Character

  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant calculates A as 12^(1/5) and attempts to find Log(A) using a calculator, but gets a different result than expected from the book.
  • Another participant suggests that the book may be old and implies that it expects the use of log tables, which were common before 1980.
  • It is noted that Log(A) is assumed to be base 10, while the participant mistakenly uses base e in their calculations.
  • Participants mention that natural logs (ln) are different from common logs (log), which could lead to confusion in calculations.
  • Suggestions are made to use Google as a supplementary tool for logarithmic calculations if a calculator is unavailable.

Areas of Agreement / Disagreement

Participants generally agree on the distinction between logarithmic bases and the potential confusion arising from using the wrong base. However, there is no consensus on the specific expectations of the textbook or the methods of calculation.

Contextual Notes

The discussion highlights the potential limitations of relying on older textbooks, which may not align with modern practices or tools for logarithmic calculations. There is also an assumption that participants are familiar with the differences between logarithmic bases.

Who May Find This Useful

This discussion may be useful for individuals interested in understanding logarithmic calculations, particularly those who encounter older mathematical texts or are learning about different logarithmic bases.

Zaent
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A=12^(1/5)
Log(A)=(1/5)Log(12)

The next part in the book says:

Log(A)=0.2158
A=1.644

I don't know how to do this without a calculator, and with a calculator I'm getting 1.24.

I'm doing e^0.2158

Can anyone please tell me where I'm going wrong here?Note: this isn't homework, just something I've come across
 
Last edited:
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How old is the book? If old (pre 1980) then the expectation is that you have and use a set of log tables.

Also log(A) implies log to base 10 i.e. 10.1258.
The standard notation for logs to base e is Ln(A).
 
Your mistake is using e and not 10. Base e is used when doing stuff with natural logs ie ln() and 10 is used when doing base 10 logs.

Google can supplement a calculator if one isn't readily available.

The old fashioned way of solving log problems was to use precomputed log tables. Alternatively you could use the ll scales of a decitrig sliderule.
 
Thank you both! I figured the book was old because it was asking me to do this, but I still knew my log knowledge was off somewhere. I'll remember the base 10 thing in future. Thanks again!
 

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