Re: DifferenitalD vs CapitalDifferenitalD
- To: mathgroup at smc.vnet.net
- Subject: [mg87938] Re: DifferenitalD vs CapitalDifferenitalD
- From: Jean-Marc Gulliet <jeanmarc.gulliet at gmail.com>
- Date: Mon, 21 Apr 2008 03:22:28 -0400 (EDT)
- Organization: The Open University, Milton Keynes, UK
- References: <fuees1$bds$1@smc.vnet.net>
fizzy wrote:
> After applying Jens correction, I was hoping to be able to use the =
> DifferentialD with x, etc. and then use the 'dx' , where 'd' here is =
> DifferentialD (just dont know how to add it here in the email), so it =
> would be a Symbol....but this didnt work....I realize I can use the =
> straight forward dx , etc. symbol but I want to highlight the =
> Differential....any way to 'fix' this?....when I type in DifferentialD =
> , from the Palette, and then add x to it and perform //Head on it , it =
> just returns DifferentialD
<snip>
Hi Jerry,
The behavior you have noticed is perfectly normal since the built-in
function *DifferentialD[]*, which can also be entered as |esc|dd|esc|
(i.e. the escape key followed by the character lowercase d twice
followed by the escape key again), is a *compound operator with built-in
meaning*. The full form of a complete expression with *DifferentialD[]*
is DifferentialD[some_expression] (one argument is required).
For instance, say we enter the expression
|esc|dd|esc|z
Its full form is
FullForm[|esc|dd|esc|z] === DifferentialD[z]
And its head is
Head[|esc|dd|esc|z] === DifferentialD
Thus, one cannot manipulate double struck lowercase d independently.
Now, if you are interested by the above character without built-in
meaning, you can get it with the following sequence of keys:
|esc|dsd|dsd|
Note that dsd stands for double struck lowercase d. Similarly, you can
get a double struck capital C by entering |esc|dsC|esc|
Finally, enter and evaluate the following sequences of keystrokes:
|esc|int|esc|z |esc|dsd|esc|z
|esc|int|esc|z |esc|dd|esc|z
They look the same. However, the first expression generates an error
message, while the second returns the expected definite integral.
Regards,
-- Jean-Marc