Re: Question about how to graph the vector field for the differential

*To*: mathgroup at smc.vnet.net*Subject*: [mg97862] Re: Question about how to graph the vector field for the differential*From*: "Sjoerd C. de Vries" <sjoerd.c.devries at gmail.com>*Date*: Tue, 24 Mar 2009 05:30:28 -0500 (EST)*References*: <gq7j9f$qeo$1@smc.vnet.net>

I have the feeling you're looking for the wrong type of plot. Your differential equation yields a family of funtions of x and these can be plotted simply by using Plot. First, solve the differntial equation: In[20]:= DSolve[y'[x] == 2 x - y[x], y[x], x] Out[20]= {{y[x] -> 2 (-1 + x) + E^-x C[1]}} Then plot it for some values of the constant C[1]: Plot[Table[2 (-1 + x) + E^-x c, {c, -10, 10, 5}] // Evaluate, {x, -1, 5}, PlotRange -> All] Cheers -- Sjoerd On Mar 23, 11:03 am, jo1e... at gmail.com wrote: > i need to graph the vector field and the family of solutions for the > DE: dy/dx=2x-y > and i tried the graph the vector field, but while i tried to use the > VectorFieldPlot it show up some kind of wierd graph... > and i cannot even get start on the "family of Solutions" > graph...searched online but still cannot figure out. > hope some pros can help me out on this...thx alot~!! > Bluefly