Re: DSolve with recursively defined equations

*To*: mathgroup at smc.vnet.net*Subject*: [mg53793] Re: DSolve with recursively defined equations*From*: pdickof at sasktel.net*Date*: Thu, 27 Jan 2005 05:41:37 -0500 (EST)*References*: <ct7psr$ld$1@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

DrBob solved my problem: >The problem is that the expressions nn'[0, d] and nn'[i, d] don't make any >sense. Try this instead: >Clear[nn, eq, in, eqns, funcs]; >iCount = 2; >eq[0] = D[nn[0, d], d] == -r nn[0, d]; >eq[i_] := D[nn[i, d], d] == r(nn[i - 1, d] - nn[i, d]); >in[0] = nn[0, 0] == 1; >in[i_] := nn[i, 0] == 0; >eqns = Flatten[Table[{eq[i], in[i]}, {i, 0, iCount}]] >funcs = Table[nn[i, d], {i, 0, iCount}] >DSolve[eqns, funcs, d] which works (Thank-you!). The second part of the problem is still unresolved. I happen to know that the solution to the ith function is nn[n_,d_] := Exp[-d r ] Sum[(r d)^i / i!, {i,0,n-1}] How would I go about getting this general form in Mathematica? Peter