How to create a symbolic general (without explicit definition) function?

Hi all,

I want to know how to create a general function in symbolic way. My goal is to examine the differentials of the overall function in terms of a variable, where there are some functions of this variable that I am not interested in. I checked some documents, all ask me to explicitly define those functions.

Here is a example I am thinking of, which is realized in the psudo code:

syms x g real
f = x*g(x);
fdx = simplify(diff(f,x))

where g is the general function that I want to create. Therefore, this code is supposed to give me the result like:

fdx = g(x)+x*ddxg(x)

Since I really don't care the expression of g(x), a representation like ddxg(x) is what I want in the result.

Thanks in advance!

Answer 1

[Prudhvi Peddagoni]

Hi,

You need to specify that g is a function of x like this:

syms x g(x)
f = x*g;
fdx = diff(f,x);

Hope this helps.

[Yunshen Huang]

Thanks! it works exactly as I want