Re: Integration (change of variable)

• To: mathgroup at smc.vnet.net
• Subject: [mg71755] Re: Integration (change of variable)
• From: Peter Pein <petsie at dordos.net>
• Date: Tue, 28 Nov 2006 06:04:10 -0500 (EST)
• Organization: 1&1 Internet AG
• References: <ekebgc\$1a\$1@smc.vnet.net>

```KFUPM schrieb:
> Dear All
>
> I have a function that to be integrated with respect to s , the
> function is :
>
> (2*E^(((-Sqrt[p] - V)*x)/2)*Î³*DifferentialD[(p - V^2)/4])/(-Sqrt[p] -
> V)
>
> What i need to to do is actually change the varible s into p (before
> the integratio) according to the relation
>
> p=4*s+V^2;
>
> How can i automatically do that (changing the variable) using
> mathematica ? Remember that i have the term "ds" which i should take
> care of when i make the change .
>
> Any help in this regard will be highly appreciated
>
> Many thanks in advance
>
> HMQ
>

Hello,

let's call your expression expr. Then

expr /. {DifferentialD -> Dt, p -> 4*s + V^2} /. Dt -> DifferentialD

gives:

(2*E^((1/2)*(-V - Sqrt[4*s + V^2])*x)*\[Gamma]*DifferentialD[s])/(-V -
Sqrt[4*s + V^2])

HTH,
PÂ²

```

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