Symbolically differentiation a function w.r.t a function
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How to differentiate with respect to ; where, with the help of symbolic math tool. I tried writing
syms f(x) g(x) h(x) x
g(x) = sqrt(f(x)^2 + x);
h(x) = diff(g(x),f(x));
but the following error pops up,
%Error using sym/diff (line 70)
%Second argument must be a variable or a nonnegative integer specifying the number of differentiations.
I am new to MATLAB and trying to understand the reason for this error and any suggestions on how can I write;
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採用された回答
darova
2020 年 1 月 19 日
Try this
syms g(x) h(x) x f
g(x,f) = sqrt(f^2 + x);
h(x,f) = diff(g(x,f),f)
2 件のコメント
その他の回答 (1 件)
Walter Roberson
2020 年 1 月 19 日
You cannot differentiate a function with respect to a different unknown function with normal calculus, because you cannot know that the functions are independent. You need Calculus of Variations to create operators for differentiating functions.
In the past I have posted examples demonstrating that the process suggested by Darova can generate the wrong answer.
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