Re: Derivative

*To*: mathgroup at smc.vnet.net*Subject*: [mg43758] Re: Derivative*From*: "extrabyte" <extrabyte22 at libero.it>*Date*: Fri, 3 Oct 2003 02:28:45 -0400 (EDT)*References*: <blcqiv$p7d$1@smc.vnet.net> <blgiq3$g61$1@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

Paul Abbott wrote: > First use the fundamental theorem of calculus: for an arbitrary > function h[x,y], we have > > D[Integrate[h[x,y],{x,y,Infinity}],y] == > Integrate[Derivative[0, 1][h][x, y], {x, y, Infinity}] - h[y, y] ok > > Now define h, > > h[x_, y_] = Simplify[g[x, y] Sinh[theta[x, y]] Cosh[theta[x, y]]^2]; > > and compute its derivative with respect to y. > > dhdy[x_, y_] = Simplify[D[h[x,y],y]]; ehm, "Simplify" or "Evaluate"? please, see http://mynotebook.supereva.it thx -- extrabyte