* /From/: Carl Mungan <mungan@usna.edu <mailto:mungan%40usna.edu>>
* /Date/: Fri, 20 Jun 2014 16:05:08 -0400
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I agree with the idea that one ought to specify what variable is being
held in a partial derivative if there is any possibility of confusion.
eg. for f(x,y) we might want the partial of f with respect to x while y
is held fixed which we would write as (curly-d f / curly-d x)
subscript{y} Fine. Or maybe you prefer no parentheses, but instead a
vertical bar separating the derivative and the subscript. But how would
you write some harder cases? Here are two for example: 1. partial of
(f/y) with respect to y while x is held fixed - specifically, where
would you put the parentheses? I've seen people put the curly-d/curly-d
x outside the parentheses in this case. I suppose one could put brackets
and parentheses, but that starts to get ugly. 2. a second partial: say
you first differentiate f with respect to x while y is held fixed, then
differentiate with respect to y while x is held fixed - where now will
you put parentheses and subscripts? These are just warmup examples. You
can probably come up with much more gnarly examples. For example, maybe
I want to specify that one is to substitute in some value such as x0 for
x at some point along the way (say I have 3 variables x,y,x).