我正在尝试subs
在枫树中使用 0 替换较长公式中的导数:
subs(diff(u(r),r) = 0, formula);
看来,如果formula
只涉及u(r)
我所期望的这个作品的一阶导数。例如,
formula := diff(u(r),r);
subs(diff(u(r),r) = 0, formula);
0
But if formula
involves second derivatives I get a diff(0,r)
in the result that won't go away even when using simplify
:
formula := diff(u(r),r,r);
subs(diff(u(r),r) = 0, formula);
d
-- 0
dr
(My actual formula
is quite long involving first and second derivatives of two variables. I know that all derivatives with respect to a certain variable are 0 and I'd like to remove them).