RE: product formula in mathematica

*To*: mathgroup at smc.vnet.net*Subject*: [mg68757] RE: [mg68702] product formula in mathematica*From*: "David Annetts" <davidannetts at aapt.net.au>*Date*: Fri, 18 Aug 2006 03:12:01 -0400 (EDT)*Sender*: owner-wri-mathgroup at wolfram.com

Hi, > Hi I am interested in doing a product over a set of indices > that are not continuous > Product [ f(x_i) , { x_i, 1,3,4,9}] Is this possible it appears > that the iterator wouldonly take sequences such as 1...10 etc. Depends exactly what you want .... There is a form of the product function that takes a step, eg. Product[i, {i, 1, 10, 2}] However, if you want something particularly unusual, then you can simulate Product by applying Times[] to a list, eg. Times @@ Range[1, 10, 2] Or Times @@ (# &) /@ {2, 3, 5, 7, 11, 13, 17, 19} Which should be the same as Product[Prime[x], {x, 8}] Regards, Dave.