Re: Integrate with unknow function
- To: mathgroup at smc.vnet.net
- Subject: [mg130228] Re: Integrate with unknow function
- From: Bob Hanlon <hanlonr357 at gmail.com>
- Date: Sun, 24 Mar 2013 04:16:25 -0400 (EDT)
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- References: <20130323072511.390976A2E@smc.vnet.net>
If g is the indefinite integral of a contrinuous function f[x] then
Using a replacement rule
ClearAll[f, g, expr];
expr = Integrate[f[d], {d, 0, 3}] -
Integrate[f[d], {d, 0, 2}];
expr /. Integrate[f[x_], {x_, a_, b_}] ->
g[b] - g[a]
-g[2] + g[3]
Alternatively, defining an upvalue for f (TagSet)
ClearAll[f, g, expr];
expr = Integrate[f[d], {d, 0, 3}] -
Integrate[f[d], {d, 0, 2}];
f /: Integrate[f[x_], {x_, a_, b_}] =
g[b] - g[a];
expr
-g[2] + g[3]
Bob Hanlon
On Sat, Mar 23, 2013 at 3:25 AM, Shan <shan.pub at gmail.com> wrote:
> Hi,
>
> I have a very rookie question as follows:
>
> Integrate[f[d], {d, 0,3}] - Integrate[f[d], {d, 0,2}]
>
> How can I get the result as f[d]? Thanks very much for any help!
>
> shan
>
- References:
- Integrate with unknow function
- From: Shan <shan.pub@gmail.com>
- Integrate with unknow function