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