Maxima Function
del (x)
del (x) represents the differential of the variable x.
diff returns an expression containing del if an independent variable is not specified. In this case, the return value is the so-called "total differential".
diff
del
Examples:
(%i1) diff (log (x)); del(x) (%o1) ------ x (%i2) diff (exp (x*y)); x y x y (%o2) x %e del(y) + y %e del(x) (%i3) diff (x*y*z); (%o3) x y del(z) + x z del(y) + y z del(x)