Differential Equation Solutions

*To*: mathgroup at yoda.ncsa.uiuc.edu*Subject*: Differential Equation Solutions*From*: uunet!sdsu.edu!stewart (Kris Stewart)*Date*: Sat, 5 May 90 10:18:55 -0700

I'm a new Mathematica user. I was hoping for a strong differential equation solving facility in Mathematica. I don't know whether I'm not using it correctly yet, or what. I started with a simple initial value problem, y''= -y, y(0)=0, y'(0)=1, and I expected the solution, y(x)=sin(x). Instead the solution was in the equivalent, but complicated, complex exponential form still. Is there a easy to simplification package that I haven't found out about? I would like to attempt more elaborate DEs, but would solutions returned in as straight forward a form as possible. Please advise. (Note, I ran this example with Maple and got precisely the results I expected. Did I purchase the wrong symbolic package?) In[3]:= DSolve[{y'[x]==w[x],w'[x]==-y[x],y[0]==0,w[0]==1},{y[x],w[x]},x] -I x 2 I x -I x 2 I x E (-I + I E ) E (1 + E ) Out[3]= {{y[x] -> ---------------------, w[x] -> ------------------}} 2 2 Thanks, in advance, for any community help I receive. Kris Stewart stewart at cs.sdsu.edu