Re: problems with DSolve

*To*: mathgroup at smc.vnet.net*Subject*: [mg99417] Re: problems with DSolve*From*: sean_incali at yahoo.com*Date*: Tue, 5 May 2009 05:42:44 -0400 (EDT)*References*: <gtnk4s$3md$1@smc.vnet.net>

Manipulate[ sol = DSolve[{x'[t] == a y[t], y'[t] == - b x[t], x[0] == 1, y[0] == 2}, {x, y}, t]; Plot[{x[t], y[t]} /. sol, {t, 0, 5}], {a, 1, 10}, {b, 1, 10}] would do it. I've added a and b to make it interesting On May 4, 1:45 pm, szymon.st... at gmail.com wrote: > hello, > > i am new to mathematica, therefore sorry if my question is trivial. I > would like to understand why the following line does not work: > > Plot[(x[t] /. DSolve[{x'[t] == y[t], y'[t] == -x[t], x[0] == = 1, y[0] > == 2}, {x, y}, t]), {t, 0, 5}] > > whereas after splitting into two lines it works: > sol = DSolve[{x'[t] == y[t], y'[t] == -x[t], x[0] == 1, y[0= ] == 2}, > {x, y}, t] > Plot[(x[t] /. sol), {t, 0, 5}] > > i would like to use Manipulate to play with boundary conditions, so > the first notation would be highly useful. > > thanks a lot for any feedback.