what does that mean? I cannot find it on the help?

Hi I need to use the 'del' operator form with both subscript and superscript acting on it. I would for example like to be able to differentiation of a function that combines a number of vectors with respect to a particular vector. I then need to take the components for example (x) corresponding to the subscript on the del operator. Is there an easy way to do this? I can perhaps make it simpler by just using the standard derivative, but dont know how to do this with respect to a vector. Could someone help out a newbie here. I can then take the dot product with a unit vector in the x direction to obtain just the x component.

The plot function will not work with the following code:

> vatt:= (r,b,rc) -> -epsilon*(cos(Pi*(r-rc)/(2*wc)))^2;

> VattR := proc(r,b)
> rc:= evalf(b*2^(1/6));if r < rc then RETURN(-epsilon) elif rc <= r and r <= (rc+wc) then RETURN(vatt(r,b,rc)) else RETURN(0) end if;
> end proc;

> plot(VattR(r,1),r=1.1..1.2);
Error, (in VattR) cannot determine if this expression is true or false: r < 1.122462048
> VattR(1.1,1);
-1.0

The functions work fine on their own....

I would like to set my sessions to show the 1D Maple sheets - however when trying the options in the menu - it still wont happen. What am I doing wrong? Help - the 2D version drives me nuts!

I would like to solve a non analytical problem. I dont know the functions behaviour explicity because it involves a number of ranges - if and then statements. How best can I say find the point at which it becomes minimum? Thanks