Re: Mixed derivative button on basic input palette
- To: mathgroup at smc.vnet.net
- Subject: [mg40675] Re: [mg40659] Mixed derivative button on basic input palette
- From: Dr Bob <majort at cox-internet.com>
- Date: Sun, 13 Apr 2003 02:17:35 -0400 (EDT)
- References: <200304120711.DAA21339@smc.vnet.net>
- Reply-to: majort at cox-internet.com
- Sender: owner-wri-mathgroup at wolfram.com
You get this answer because the "box to the right" ends up containing x^3 only. The mixed partial of that is zero, and multiplying that by y^4 gives 0. You can do better by putting () in that box, and putting x^3 y^4 between the parentheses. Then you get the right answer. It is very annoying that the box disappears as soon as we put anything in it, and leaves us with no way to tell what's connected to the partial derivative. The same thing happens with the summation symbol, etc. PartialD is an operator, so it is supposed to bind to its nearest following neighbor and make it the argument. So, I'm not sure we can call this a bug. I do call it annoying, though. Bobby On Sat, 12 Apr 2003 03:11:27 -0400 (EDT), Will Self <wself at msubillings.edu> wrote: > 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
- References:
- Mixed derivative button on basic input palette
- From: wself@msubillings.edu (Will Self)
- Mixed derivative button on basic input palette