Variable Substitution Using Symbolic Functions

syms A(t) B(t) C(t) t

syms X Y Z

D=A+B+C

D(t) =

Ds=subs(D,[A,B,C],[X,Y,Z])

Ds(t) =

I'm trying to substitute a time function for dummy variables that aren't interpreted as functions of time. Here I would assume X,Y,Z would not be functions of t since X,Y,Z aren't declared as such.

My goal is to treat both x(->a) and dx/dt(->b) as two separete variables that I can differentiate to get dx/dt and dx^2/dt^2(->c)

[madhan ravi]

Expected output?

[Angel Quintanilla]

the equations are pretty long but for example:

Ds=X+Y+Z where XYZ represent dummy variables and not not functions of time.

Hence Ds is not Ds(t) a funtion of time but of XYZ which are variables and not functions

[madhan ravi]

See my answer below ;) then if you don’t want the equation to be a function of time.

Answer 1

[madhan ravi]

Use formula()