Finding Symbolic Matrix Derivative
Afficher commentaires plus anciens
I have the following Matrix and I wish to find its derivative,
A = 

Please note that ϕ and θ in this matrix are functions of time t.
I have the following MATLAB code,
syms phi theta t real
A = [1 , 0 , -sin(theta) ;...
0 , cos(phi) , cos(theta) * sin(phi) ;...
0 , -sin(phi) , cos(phi) * cos(theta)];
Adot = diff(A); % this isn't giving the result I expect
So I tried,
syms phi theta t real
A = [1 , 0 , -sin(theta) ;...
0 , cos(phi) , cos(theta) * sin(phi) ;...
0 , -sin(phi) , cos(phi) * cos(theta)];
phi(t) = phi;
theta(t) = theta;
Adot = diff(A , t); % this also isn't working
The result I want is,

Please help me to get this result.
Réponses (1)
Declare theta and phi as functions, and then substitute after differentiating A
syms phi(t) theta(t) phi_dot(t) theta_dot(t)
A=[1 0 -sin(theta);0 cos(phi) cos(theta)*sin(phi);0 -sin(phi) cos(phi)*cos(theta)]
subs(diff(A,t),diff([phi(t) theta(t)]),[phi_dot(t) theta_dot(t)])
Note that this result is not the same as the expected result in the question, which appears to have some terms that are incorrect.
Catégories
En savoir plus sur Operations on Strings dans Centre d'aide et File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!

