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Re: RE: Re: Mixed derivative button on basic input palette

  • To: mathgroup at smc.vnet.net
  • Subject: [mg40788] Re: [mg40748] RE: [mg40737] Re: Mixed derivative button on basic input palette
  • From: Dr Bob <majort at cox-internet.com>
  • Date: Thu, 17 Apr 2003 03:36:14 -0400 (EDT)
  • References: <200304160535.BAA20180@smc.vnet.net>
  • Reply-to: majort at cox-internet.com
  • Sender: owner-wri-mathgroup at wolfram.com

>> Perhaps in such cases the palette should include parentheses around the 
>> selection box.

I like that idea!

Bobby

On Wed, 16 Apr 2003 01:35:14 -0400 (EDT), David Park <djmp at earthlink.net> 
wrote:

> 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
> 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
> 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
>
>
>



-- 
majort at cox-internet.com
Bobby R. Treat



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