Symbolically differentiation a function w.r.t a function
6 views (last 30 days)
Show older comments
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;
0 Comments
Accepted Answer
darova
on 19 Jan 2020
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 Comments
More Answers (1)
Walter Roberson
on 19 Jan 2020
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.
See Also
Categories
Find more on Calculus in Help Center and File Exchange
Products
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!