Re: newbie: how to define, typeset a multi-rule function?

*To*: mathgroup at smc.vnet.net*Subject*: [mg96813] Re: newbie: how to define, typeset a multi-rule function?*From*: Tom Roche <tlroche at gmail.com>*Date*: Wed, 25 Feb 2009 04:06:19 -0500 (EST)*References*: <go0j63$n28$1@smc.vnet.net>

Tom Roche Feb 24, 5:46 am (rearranged) >> I'm trying to create a notebook that typesets a particular >> mathematical function, and then solves it. I.e. I'll have a line of text that shows the function to solve, then another line of input that solves it when evaluated. Like a homework problem. >> The function has 2 parts or rules: it returns k (a constant) for one >> part of its domain, and 0 otherwise. This is typically typeset with >> the function name and the equals sign on one line, then a large left >> curly bracket (or brace) centered on that line, then each rule on a >> separate line with all the rule lines to the right of the bracket. >> I suspect in this case I just need to know what the appropriate >> term is for what I'm trying to create. However I've tried searching >> the docs for various permutations of multi-rule or multi-line >> function, and even googling, to no avail. dh Tue, Feb 24, 2009 at 7:20 AM > there is "Piecewise". doh! That's the term I was trying to remember. > In your case: Piecewise[{{k,0<=x<1}},0] Indeed, and I can solve that like part1ex1fn = {Piecewise[{{k \[Chi], 0 <= \[Chi] <= 1}}, 0]} Solve[ First[ Integrate[part1ex1fn, {\[Chi], -\[Infinity], \[Infinity]}] ] == 1, k ] (though I assume there's a better way). But how to layout the equation as text? >> For an example in a math layout, I can almost typeset the function >> in OpenOffice Math like f_x(%chi) = left lbrace stack {k if %chi in >> [0,1] # 0 otherwise} right rbrace (except that I don't want the >> closing brace, but that's another problem). I tried to create this >> using the palettes, but I didn't see one that did multiline >> brackets. DrMajorBob Tue, Feb 24, 2009 at 10:45 AM > As you're not speaking "Mathematica", I'm trying. Ya gotta learn somehow. > perhaps this is the function you want: > Subscript[f, x][chi_] = Piecewise[{{k, 0 <= chi <= 1}}] Yep, that sure looks like it, but ... > I used the "special characters" palette to enter \[Chi]. ... where's the palette item to get the left brace? > You can also copy/paste the [line above] to Mathematica, press Enter > to evaluate the line, and the bracketed version should appear. That it does, but it doesn't show the f_x(\[Chi]); i.e. the right-hand side appears, but not the LHS. How do I get both the LHS and RHS to appear as text? TIA, Tom Roche <Tom_Roche at pobox.com>

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**Re: newbie: how to define, typeset a multi-rule function?**

**Re: newbie: how to define, typeset a multi-rule function?**