How to differentiate a differential function with a differential variable using symbolic toolbox?

%My matlab code

syms phi(t) t 
f= sin(sym(phi(t)))
% Differentiation of above equation w.r.t t
f_dot=sym(diff(f,'t'))
% Differentiation of above equation w.r.t diff(phi(t),t)
x=diff(f_dot,diff(phi(t),t))

I'm getting error in the in the last step, when I'm trying to differentiat the f_dot equation with diff(diff(phi(t),t))

%matlab output

f_dot = cos(phi(t))*diff(phi(t), t)

Error using mupadmex

Error in MuPAD command: Invalid variable. [stdlib::diff]

Error in sym/diff (line 44)

    R = mupadmex('symobj::diff', S.s, x.s, int2str(n));

Error in handle (line 7)

x=diff(f_dot,diff(phi(t), t)

Answer 1

[Walter Roberson]

This is not possible in MuPAD. You will need to do a change of variables. Doing a naive substitution of variables can lead to incorrect results .

[Harish Babu Kankanala]

thanks Walter

Answer 2

[Kadiatou Youla]

i am the differentiate function in the matlab but i can not get it