Re: unevaluatedsdi integral

*To*: mathgroup at smc.vnet.net*Subject*: [mg19500] Re: unevaluatedsdi integral*From*: "David Bailey" <db at salford-software.com>*Date*: Sat, 28 Aug 1999 15:53:20 -0400*Organization*: University of Salford, Salford, Manchester, UK*References*: <7q206n$q8i@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

CORNIL Jack Michel <jmcornil at club-internet.fr> wrote in message news:7q206n$q8i at smc.vnet.net... > Hello, > > > Does someone knows elegant mean of working (with MATHEMATICA) with > unevaluated integral in order to show change of variables, integration > by parts, simplification of the integrang ? > Yes, The Salford Colour Maths package (http://www.salford.co.uk/mathematica) allows unevaluated integrals (and summations). The integrals are represented by 'Integral' rather than 'Integrate' and display using a slightly thicker font to distinguish them from regular integrals. You can do all the things you mention, and also convert them to regular integrals when required. The package also lets you colour parts of expressions so that particular algebraic transformations can by targeted at certain bits of an expression. There is one small problem with unevaluated integrals and similar objects - they do not differentiate (with respect to a parameter) nicely. This is because the standard Mathematica 'D' operator seems to apply the chain rule to objects such as Integral[f[x],{x,0,10}] as if Integral was a regular function. The only solution would seem to be an unevaluated derivative operator. I have one of these, but have not yet added it to the above package. Contact me for more details. David Bailey