I have an interface function field called fstring.

it read the string value in it and is pass to the graphics view as an analyticCurve with
X() = x
Y() = %fstring%

i am able to draw a nice graph say sin(x-t). perfect!

but how do i make a d(sin(x-t)/dt ?

i tried putting an evolution page

d(fstring)/dt = velocity

and make another analyticCurve

X() = x
Y() = velocity

doesn't seem to work, any idea how to make graph of d(fstring)/dt.


if you want to see my xml, just delete the evolution page and it will run ;D