On Mon, Nov 16, 2009 at 12:23 PM, Conrad Schiff <gravmath at yahoo.com> wrote:
> A trivial workaround is available by defining an intermediate
> expression vx_sho = diff(x,t) and then using ev(vx_sho,t=0)
> so this isn't a serious problem however it is annoying and
> the process looks so much cleaner if I don't have to define vx.
There is an automatically defined "last result" variable which
obviates the need for a named intermediate variable.
It is named % at the command line and %% in a composite
expression (block or lambda).
e.g. maybe something like:
diff (my_expr, t);
ev (%, t=0);
Sometimes it's clearer to break up a computation into
steps in which % from one step is processed in the next.
Maybe that's helpful to you.
best
Robert Dodier