Re: Mixed derivative button on basic input palette
- To: mathgroup at smc.vnet.net
- Subject: [mg40737] Re: Mixed derivative button on basic input palette
- From: wself at msubillings.edu (Will Self)
- Date: Tue, 15 Apr 2003 04:00:18 -0400 (EDT)
- References: <b7b09v$qqh$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Thanks one and all. I'm not a palette guy really. Actually I'm sort of a Mathematica 2 guy. But my students like the palettes. Observe that this behavior is identical with that of the one-variable derivative button on the palette, for example, if you use the palette button to do the derivative of x^2Sin[x], you get the wrong answer unless you remember the parentheses. Remembering the parentheses strikes me as a lot harder to do than just typing in the D notation. It is remarkable that there is no visual clue (such as a pink window) to show that the cursor is no longer in the input box generated by the palette. Furthermore, the behavior is *not* consistent with the way the summation button works. There, you can enter the sum as x goes from 1 to 3 of x^2Sin[x], and it comes out right; no need for parentheses. It seems like a fiendish design to mislead poor students. Will "David Park" <djmp at earthlink.net> wrote in message news:<b7b09v$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