Hello, I want to know if it is possible to change the diff function to a variable which i want to call it like the following. (change it in the answer given by matlab). * %diff(a(t), t)=a_dot * %diff(a(t), t, t)=a_doubledot * %diff(d(t), t)=d_dot * %diff(d(t), t, t)=d_doubledot * This is my code: clc syms a(t) r d(t) r=[d*cos(a);d*sin(a);0]; r_dot=diff(r); r_doubledot=diff(r_dot); BCN=[cos(a),sin(a),0;-sin(a),cos(a),0;0,0,1]; br_doubledot=BCN*r_doubledot; br_doubledot=simplify(br_doubledot) Answer: br_doubledot(t) = diff(d(t), t, t) - d(t)*diff(a(t), t)^2 d(t)*diff(a(t), t, t) + 2*diff(a(t), t)*diff(d(t), t) 0

Change the function in a matrix (diff(f(x), x) to some variable.

Tijmen Godfroid

2018 10 10

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Hello,

I want to know if it is possible to change the diff function to a variable which i want to call it like the following. (change it in the answer given by matlab).

%diff(a(t), t)=a_dot
%diff(a(t), t, t)=a_doubledot
%diff(d(t), t)=d_dot
%diff(d(t), t, t)=d_doubledot
This is my code:

clc
syms a(t) r d(t) 
r=[d*cos(a);d*sin(a);0];
r_dot=diff(r);
r_doubledot=diff(r_dot);
BCN=[cos(a),sin(a),0;-sin(a),cos(a),0;0,0,1];
br_doubledot=BCN*r_doubledot;
br_doubledot=simplify(br_doubledot)
Answer:
br_doubledot(t) =
                 diff(d(t), t, t) - d(t)*diff(a(t), t)^2
   d(t)*diff(a(t), t, t) + 2*diff(a(t), t)*diff(d(t), t)
                                                       0