Re: unevaluated expression

• To: mathgroup at smc.vnet.net
• Subject: [mg77179] Re: unevaluated expression
• From: Jean-Marc Gulliet <jeanmarc.gulliet at gmail.com>
• Date: Tue, 5 Jun 2007 06:44:39 -0400 (EDT)
• Organization: The Open University, Milton Keynes, UK
• References: <f40gan\$628\$1@smc.vnet.net>

```juliok at verizon.net wrote:
> How do you write a function such as
>    example[f_]:= ......
>
> so that when entering example[#^2] Mathematica will respond with
>
> integral_symbol x^2 dx = x^3 /3
>
> where integral_symbol is the standard math symbol, exponents are
> superscripts, etc. I tried Hold[], Unevaluated[], nothing seems to
> work.
>
> Thanks
>
>
> Julio

Hi Julio,

Assuming I have correctly understood what you tried to do, HoldForm is
the function you need on the LHS. For instance,

In[1]:=
HoldForm[Integrate[x^2, x]] == Integrate[x^2, x]
example[f_] := HoldForm[Integrate[f, x]] ==
Integrate[f, x]
example[x^2]
example2[fun_, var_:x] :=
HoldForm[Integrate[fun, var]] == Integrate[fun, var]
example2[x^3]
example2[(t - 3)^(1/2), t]

Out[1]=
3
2        x
Integrate[x , x] == --
3

Out[3]=
3
2        x
Integrate[x , x] == --
3

Out[5]=
4
3        x
Integrate[x , x] == --
4

Out[6]=
2         3/2
Integrate[Sqrt[-3 + t], t] == - (-3 + t)
3

Note that within a notebook, Integrate will be displayed as the integral
symbol. Also, example2 is more flexible than example.

Hope this helps,
Jean-Marc

```

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