Re: Subscript Bug?

*To*: mathgroup at smc.vnet.net*Subject*: [mg90138] Re: Subscript Bug?*From*: dh <dh at metrohm.ch>*Date*: Mon, 30 Jun 2008 04:54:05 -0400 (EDT)*References*: <g47l28$t66$1@smc.vnet.net>

Hi Aaron, the second line defines H as 200. Parsing the third line from left to right, Subscript[H,1] is encountered, that has no value. Therefore, it is parsed further and H is replaced by 200. Therefore, Tanh[Subscript[H,1]] gives Tanh[Subscript[200, 1]]. The second time the first line is executed, H is replaced by 200 and you define Subscript[200,1]= 110; You may check this by: Subscript[200,1]. Parsing the third line, Mathematica sees Subscript[H,1, this now have a value of 110. Therefore, you get: Tanh[110] The pitfall here is, that you gave a value to the name of a subscripted variable. If you want to do this, it is better if you use H1 instead of Subscript[H,1] in your calculations and eventually specify a format like: Format[H1]=Subscript["H",1] for the print out. hope this helps, Daniel Aaron Fude wrote: > Hi, > > I have this code in a cell: > > Subscript[H, 1] = 110; Subscript[H, 2] = 90; > H = Subscript[H, 1] + Subscript[H, 2]; > Tanh[Subscript[H, 1]] > > The first time I execute the cell, I get > > Tanh[Subscript[200, 1]] > > which of course is nonsense. > > A second execution, yields the correct answer: > > Tanh[110] > > Is this a feature that I don't understand or a bug? > -- Daniel Huber Metrohm Ltd. Oberdorfstr. 68 CH-9100 Herisau Tel. +41 71 353 8585, Fax +41 71 353 8907 E-Mail:<mailto:dh at metrohm.com> Internet:<http://www.metrohm.com>