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

  1. Oct 9, 2013 #1
    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!
  2. jcsd
  3. Oct 9, 2013 #2


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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:
  4. Oct 9, 2013 #3


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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.
  5. Oct 9, 2013 #4


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    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
  6. Oct 9, 2013 #5
    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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