Time derivative then partial derivative of symbolic function

25 次查看（过去 30 天）

Lauran Leermakers 2020-10-22

评论： Star Strider 2020-10-22

In the following code I would like to take the time derivative and then the partial derivative to x and/or y of a symbolic function.

syms x(t) y(t)
f = 4*x^3 + 3*y^2;
g = diff(f,t);
h = diff(g,x(t));

In line 4 an error tells me "Second argument must be a variable or a nonnegative integer specifying the number of differentiations."

How can I alter my code such that I can take this partial derivative?

Star Strider 2020-10-22

Just do:

h = diff(g,x);

and it works.

I have succesfully upgraded to R2020b. Your suggestion works now! Thanks again

Star Strider 2020-10-22

As always, my pleasure!

Mathematics and Optimization Symbolic Math Toolbox Mathematics Assumptions

在 Help Center 和 File Exchange 中查找有关 Assumptions 的更多信息

R2020a

Find the treasures in MATLAB Central and discover how the community can help you!

Translated by