DSolve change in v5 -- undocumented error message

*To*: mathgroup at smc.vnet.net*Subject*: [mg46751] DSolve change in v5 -- undocumented error message*From*: Gareth Russell <gjr2008 at columbia.edu>*Date*: Fri, 5 Mar 2004 01:47:08 -0500 (EST)*Organization*: Columbia University*Sender*: owner-wri-mathgroup at wolfram.com

Hi, The following expression used to work in v4: DSolve[{n'[t] == r*n[t]*(1 - n[t]/k), n[0] == n0}, n[t], t] In v5, I get the message "DSolve::bvfail: For some branches of the general solution, unable to solve the conditions." Clicking on the "More" link takes me to a page in the Help Browser with "Notes for this message have not yet been added." Interestingly, the expression without initial conditions works just like before In[31]:= DSolve[{n'[t] == r*n[t]*(1 - n[t]/k)}, n[t], t] Out[31]= \!\({{n[t] \[Rule] \(\[ExponentialE]\^\(r\ t + k\ C[1]\)\ k\)\/\(\(-1\) + \ \[ExponentialE]\^\(r\ t + k\ C[1]\)\)}}\) Does anyone know what is being done differently in v5. And more practically, is there a way to recover v4's ability to get a solution. Perhaps with assumptions? Many thanks, Gareth Russell Columbia University