Re: Hold & Evaluate

*To*: mathgroup at smc.vnet.net*Subject*: [mg129910] Re: Hold & Evaluate*From*: "djmpark" <djmpark at comcast.net>*Date*: Mon, 25 Feb 2013 02:21:18 -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*: <4703464.30423.1361680665289.JavaMail.root@m06>

Jakub, The following evaluates the denominator and then wraps it in a HoldForm. Table[n/HoldForm @@ {n + 0.1 (n + 1)}, {n, 1, 15}] % // ReleaseHold {1/1.2, 2/2.3, 3/3.4 ,4/4.5 ,5/5.6, 6/6.7, 7/7.8, 8/8.9, 9/10., 10/11.1, 11/12.2, 12/13.3, 13/14.4, 14/15.5, 15/16.6} {0.833333, 0.869565, 0.882353, 0.888889, 0.892857, 0.895522, \ 0.897436, 0.898876, 0.9, 0.900901, 0.901639, 0.902256, 0.902778, \ 0.903226, 0.903614} The following Presentations routine isolates Subexpressions by placing them within Tooltips that indicate they are held expressions and that also give some control on whether there are parentheses and a key for selective release. There are many cases, in physics say, where one might want to bind various constant expressions together and prevent them from being separated during simplification routines. << Presentations` Table[n/CreateSubexpression[n + 0.1 (n + 1), False], {n, 1, 15}] % // ReleaseSubexpressions[] Which gives the same output as above except the denominators of the fractions have Tooltips of "held" on them. David Park djmpark at comcast.net http://home.comcast.net/~djmpark/index.html From: =A9er=FDch Jakub [mailto:Serych at panska.cz] Dear mathgroup, I would like to generate sequence in the form: 1/1.2, 2/2.3, 3/3.4, 4/4.5, etc. It is very simple by a Table function: Table[n/(n + 0.1 (n + 1)), {n, 1, 15}] but as there are real numbers in denominators, Mathematica evaluates all and generates something like: {0.833333, 0.869565, 0.882353, 0.888889, 0.892857, 0.895522, etc.} How to evaluate numerators and denominators separately and print the sequence in that "fraction like" form? I tested: #[[1]]/#[[2]] & /@ Table[{n, n + 0.1 (n + 1)}, {n, 1, 15}] and than used Hold[] and Evaluate[]: Hold[Evaluate[#[[1]]]/Evaluate[#[[2]]]] & /@ Table[{n, n + 0.1 (n + 1)}, {n, 1, 15}] But it doesn't work as the Hold has "veto" power over any evaluation. Thanks in advance for any idea, how to do it Jakub