Differentiate with Respect to Derivative
1 Ansicht (letzte 30 Tage)
Ältere Kommentare anzeigen
Hi,
I have this code:
syms x(t) m k t
T = m/2*diff(x(t),t)^2;
D1 = diff(T,diff(x(t), t))
But I got this error:
Second argument must be a variable or a nonnegative integer specifying the number of differentiations.
Do you know how can I have the differentiate with respect to derivative?!
0 Kommentare
Antworten (1)
David Goodmanson
am 12 Sep. 2022
Hello Mitra,
what version of Matlab are you running? Running your code in 2021b gives
D1 =
m*diff(x(t), t)
as desired. Running it in 2019b gives the error message that you have. So there must have been some improvements in the interim. The following workaround, though, runs in 2019b and gives the correct result:
syms x(t) m k t dxdt
T = m/2*diff(x(t),t)^2;
T = subs(T,diff(x(t),t),dxdt);
D1 = diff(T,dxdt);
D1 = subs(D1,dxdt,diff(x(t),t))
D1 =
m*diff(x(t), t)
Siehe auch
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!