Re: How to calculate the partial derivative?

*To*: mathgroup at smc.vnet.net*Subject*: [mg128747] Re: How to calculate the partial derivative?*From*: Bob Hanlon <hanlonr357 at gmail.com>*Date*: Fri, 23 Nov 2012 03:26:33 -0500 (EST)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com*Delivered-to*: l-mathgroup@wolfram.com*Delivered-to*: mathgroup-newout@smc.vnet.net*Delivered-to*: mathgroup-newsend@smc.vnet.net*References*: <20121122004814.D4F1A6894@smc.vnet.net>

Use Simplify; however, the specific resultant form is determined by the canonical order of the variables. bb1 = -Det[{{1, 1, 1}, {y2, y3, y4}, {z2, z3, z4}}] // Simplify y4 (-z2 + z3) + y3 (z2 - z4) + y2 (-z3 + z4) -Det[{{1, 1, 1}, {y2, y3, y4}, {x2, x3, x4}}] // Simplify x4 (y2 - y3) + x2 (y3 - y4) + x3 (-y2 + y4) Bob Hanlon On Thu, Nov 22, 2012 at 7:23 PM, Tang Laoya <tanglaoya1989 at gmail.com> wrote: > Dear Prof. Hanlon, > > Thank you very much for your kindly reply for my previous question. > > Now I have another question about factor: > > I wish mathematica give me an express which I can coding by Fortran with > smallest number of floating operations. For example, if I have: > > bb1 = -Det[{{1, 1, 1}, {y2, y3, y4}, {z2, z3, z4}}]; > > the result by mathematica is: > y3 z2 - y4 z2 - y2 z3 + y4 z3 + y2 z4 - y3 z4 > > I wish it output the result like this: > z2 (y3-y4) - z3 (y2-y4) + z4 (y2-y3) > > > What should I do? > > > Thanks, > Tang Laoya

**References**:**How to calculate the partial derivative?***From:*Tang Laoya <tanglaoya1989@gmail.com>