Re: is this solvable?

*To*: mathgroup at smc.vnet.net*Subject*: [mg56625] Re: is this solvable?*From*: ames kin <ames_kin at yahoo.com>*Date*: Sat, 30 Apr 2005 01:28:17 -0400 (EDT)*Sender*: owner-wri-mathgroup at wolfram.com

Thanks to all those who have replied. a'[t] + b'[t] == -p1 a[t] - p2 b[t] is a result of operating on two odes that have 3 variables. { a'[t] == -p1 a[t] - p3 c[t] b'[t] == p3 c[t] - p2 b[t] } adding the two equations allows me to get rid of p3 c[t] terms. ( Above system comes from a piece wise defined ODE system after a certain time point.) but the problem was that I end up with the a'[t]+ b'[t] dan's suggestion of setting b[t]-> b0 allows a particular form of solutions to be found using the normal DSolve syntax. Don Taylor <dont at agora.rdrop.com> wrote: In comp.soft-sys.math.mathematica you write: >a'[t] + b'[t]== -p1 a[t] - p2 b[t] >where {a[0]== a0, b[0]== b0} >is this solvable in Mathematica? If so, how will I go about doing so? >let's assume a[0]== a0, and b[0]==b0 >if symbolic solution isn't possible, then intial conditions of >a[0]== 1, and b[0]==0.5 couild be used...(or any other numbers for that >matter) >thanks in advance. Can you give me a bit more information about your problem? I don't think I understand enough about what you are doing to try to offer ideas. Thank you