Re: Change integral variables
- To: mathgroup at smc.vnet.net
- Subject: [mg88213] Re: Change integral variables
- From: dh <dh at metrohm.ch>
- Date: Mon, 28 Apr 2008 04:40:51 -0400 (EDT)
- References: <fv1fep$es1$1@smc.vnet.net>
Hi,
to prevent evaluation, there is Hold or HoldForm.
To change variable of integration without evaluating the integral, we
may use Hold or HoldForm which prints nicer.
Hold[Integrate[Sin[Sqrt[x]],x]]
/.Hold[Integrate[body_,var_]]:>(Hold[Integrate[body1,var]]/.{body1->2
body /.x->t^2,var->t})
note that we take care of dx=2 dt by writing body1-> 2 body. Note also
that the first Rule must be delayed.
hope this helps, Daniel
Budaoy wrote:
> In Mathematica, how can I change integral variables? For example in
> integration:
>
> Integrate[Sin[Sqrt[x]], x] if I want to use t^2=x to instead x in the
> integral, how can I achieve this?
>
> PS: Does Mathematica have a inertial form of some symbolic command,
> for instance, the above integration, if I only want an integration
> form but not an answer, what can I do?
>
> Thanks.
>