Re: DSolve
- To: mathgroup at smc.vnet.net
- Subject: [mg83266] Re: [mg83169] DSolve
- From: "W. Craig Carter" <ccarter at mit.edu>
- Date: Fri, 16 Nov 2007 05:35:04 -0500 (EST)
- References: <200711131200.HAA05087@smc.vnet.net>
> eqn = D[u[x], {x, 2}] + \[Lambda]^2 (0.25 - x^2) u[x] == 0
> DSolve[{eqn, u[-1/2] == 0, u[1/2] == 0}, u[x], x]
>
> This returns {{u[x] -> 0}} while another CAS system
> returns a solution
Dear Raj,
Math6 will find a solution in terms of ParabolicCylinderD
for undetermined coefficients. This function and WhittikerW
are related to the Hypogeometric functions. I can't see why
your extra conditions are giving a zero:
ParabolicCylinderD has zeroes for real lambda. Perhaps you
will have to find the eigenvalues, lambda, with a rootsolver
for ParabolicCylinderD.
Trying Assuming[\[Lambda] \[Element] Reals, DSolve[{eqn},
u[x], x]]
- References:
- DSolve
- From: Raj <rajanikanth@gmail.com>
- DSolve