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RE: Re: Mixed derivative button on basic input palette

• To: mathgroup at smc.vnet.net
• Subject: [mg40748] RE: [mg40737] Re: Mixed derivative button on basic input palette
• From: "David Park" <djmp at earthlink.net>
• Date: Wed, 16 Apr 2003 01:35:14 -0400 (EDT)
• Sender: owner-wri-mathgroup at wolfram.com

Will,

I think you're right. It is not intuitive or user-friendly. Perhaps in such
cases the palette should include parentheses around the selection box.

David Park
djmp at earthlink.net
http://home.earthlink.net/~djmp/

From: Will Self [mailto:wself at msubillings.edu]
To: mathgroup at smc.vnet.net

Thanks one and all.  I'm not a palette guy really.  Actually I'm sort
of a Mathematica 2 guy.  But my students like the palettes.

Observe that this behavior is identical with that of the one-variable
derivative button on the palette, for example, if you use the palette
button to do the derivative of x^2Sin[x], you get the wrong answer
unless you remember the parentheses.  Remembering the parentheses
strikes me as a lot harder to do than just typing in the D notation.
It is remarkable that there is no visual clue (such as a pink window)
to show that the cursor is no longer in the input box generated by the
palette.

Furthermore, the behavior is *not* consistent with the way the
summation button works.  There, you can enter the sum as x goes from 1
to 3 of x^2Sin[x], and it comes out right; no need for parentheses.

It seems like a fiendish design to mislead poor students.

Will


"David Park" <djmp at earthlink.net> wrote in message
news:<b7b09v$qqh$1 at smc.vnet.net>...
> Will,
>
> You have to put parentheses around x^3 y^4, otherwise you are calculating
>
> D[x^3, x, y]y^4
>
>
> David Park
> djmp at earthlink.net
> http://home.earthlink.net/~djmp/
>
> From: Will Self [mailto:wself at msubillings.edu]
To: mathgroup at smc.vnet.net
>
> Would you try the mixed derivative button on your basic input palette
> and see if it works?  Click on the button and put x and y in the two
> subscripts, then put x^3y^4 in the box to the right.  I get 0, both in
> versions 4.0 and 4.2. It seems that the Wolfram people could have
> fixed this bug by now.
>
> Of course, the kernel is fine, and
> D[x^3y^4, x, y] gives the correct output 12x^2y^3.
>
> I hope I'm not flogging a dead horse.  I did a search but found
> nothing on this.
>
> Thanks,
>
> Will

• Follow-Ups:
  • Re: RE: Re: Mixed derivative button on basic input palette
    • From: Dr Bob <majort@cox-internet.com>