Re: dx/d(x+y) ?

On 13 Oct 2005 15:27:39 -0700, matt271829-news@xxxxxxxxxxx wrote:

>
>David C. Ullrich wrote:
>> On 13 Oct 2005 01:06:04 -0700, "Budge" <bitsandjokes@xxxxxxxxx> wrote:
>>
>> >Hi,
>> >
>> >How do you compute
>> >
>> >dx/d(x+y)
>>
>> You don't, because it's meaningless.
>>
>
>But if y = f(x) then the answer is 1/(1+dy/dx), right?

The original specified that we were talking about
partial derivatives, from which I deduced that
x and y were independent variables.

If we're talking about just one variable x and
y = f(x) then the notation is still officially
meaningless, but yes, under certain conditions
it would follow that x was also a function of
x + y, and in that case the derivative of that
function would be 1/(1 + dy/dx).


************************

David C. Ullrich
.

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