problems with DSolve

*To*: mathgroup at smc.vnet.net*Subject*: [mg99375] problems with DSolve*From*: szymon.stoma at gmail.com*Date*: Mon, 4 May 2009 06:00:40 -0400 (EDT)

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.