The way we write ln(x) to the power of a

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Discussion Overview

The discussion revolves around the notation used for expressing powers of functions, specifically comparing trigonometric functions and logarithmic functions. Participants explore the conventions in writing expressions like (cos x)a and (ln x)a, questioning the consistency and clarity of these notations across different types of functions.

Discussion Character

  • Debate/contested

Main Points Raised

  • One participant notes that while (cos x)a can be expressed as cosax, similar expressions for logarithmic functions like (ln x)a are not commonly used.
  • Another participant asserts that many textbooks adopt the convention of writing powers of functions in a certain way, suggesting it is widely accepted.
  • A different viewpoint mentions that logarithmic functions rarely appear with powers compared to trigonometric functions, which often do.
  • One participant shares their advisor's preference for writing squared functions as f2(x), expressing discomfort with this notation but acknowledging its aesthetic appeal in final presentations.
  • Concerns are raised about the ambiguity of the notation fa(x), which could imply either f(x)a or an iterative application of the function, depending on context.

Areas of Agreement / Disagreement

Participants express differing opinions on the clarity and commonality of notation for powers of functions, indicating that no consensus exists on the best approach to writing these expressions.

Contextual Notes

Participants highlight the potential ambiguity in notation and the context-dependent interpretation of function powers, suggesting that clarity may vary based on the specific function being discussed.

johann1301
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I have learned that (cos x)a can be written as cosax. And like wise for sin x and tan x.

How come we don't write (ln x)a as lnax or (log x)a as logax?

I just think it seems smarter when its written with as few symbols as possible.

(Or perhaps its just my textbook which don't write it this way?)

Thanks in advance!
 
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LOTS of textbooks use that convention. I will go as far as to say it is the most common convention. :smile:
 
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Personally, I hardly ever see logs with powers (except in a couple of circumstances), while trigs with powers (especially squared) are a common occurrence.
 
My advisor has gone so far as to tell me when I square any function I should write it as f2(x), which I personally don't like but what am I going to do about it (I would rather write f(x)2). I will admit that it makes the final writeup a little cleaner looking
 
The notation fa(x) is a little bit ambiguous because it can mean either f(x)a or f(f(...f(x)...)).

You can usually work out the meaning from context. If f is a trig function, you are probably okay, since in most situations it does not make sense to iterate the sine function. But both log(log(x)) and (log(x))2 are potentially useful things.
 

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