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Re: Hold and Equal

• To: mathgroup at smc.vnet.net
• Subject: [mg73834] Re: Hold and Equal
• From: Peter Pein <petsie at dordos.net>
• Date: Thu, 1 Mar 2007 06:23:46 -0500 (EST)
• References: <200702261112.GAA27677@smc.vnet.net> <200702271044.FAA23846@smc.vnet.net> <es3i9c$ntm$1@smc.vnet.net>

Murray Eisenberg schrieb:
> OK, that does what I explicitly asked for, but what I asked for was an 
> oversimplified case of what I actually wanted...
...
> Moreover, if I try, say,
> 
>    step[Hold[Integrate[x^2,x]]]
> 
> then Hold appears on both sides of the resulting equality.
> 
> What I'm after is something that will allow me to show an equation of 
> the form, say,
> 
>      integral = evaluatedIntegral
> 
> where the left-hand side uses the integral sign and a "dx" (as an 
> unevaluated expression), the right-hand side evaluates that integral, 
> and the entire expression appears in traditional mathematical form.
> ...

And the attribute HoldAll (or HoldFirst) doesn't work in your version?

(the HoldForm can be seen, because I converted output to InputForm before
copy/paste). It is invisible in the Notebook when using Standard- or
TraditionalForm

step[Integrate[x^2, x]]

--> HoldForm[x^3/3 = x^3/3]

SetAttributes[step, HoldAll]
step[Integrate[x^2, x]]

--> HoldForm[Integrate[x^2, x] = x^3/3]

Peter