You should probably wrap a "factor" around this, to try to get rid of as many del()'s as possible.
E.g.,
(%i1) diff(x^2*y^2)/diff(x*y);
2 2
2 x y del(y) + 2 x y del(x)
(%o1) -----------------------------
x del(y) + y del(x)
(%i2) %,factor;
(%o2) 2 x y
At 11:31 PM 2/19/2012, Robert Dodier wrote:
>On 2/16/12, Stavros Macrakis <macrakis at alum.mit.edu> wrote:
>
>> Actually, a little reflection makes it clear that diff(f(x),g(x)) should
>> not be an error or a noun form, because in fact it is perfectly
>> well-defined and meaningful:
>>
>> diff(A,B) == ev(diff(A)/diff(B),del)
>
>Looks OK to me. OK by me to merge this in.
>
>best
>
>Robert Dodier