Hello,
I am currently using MATLAB R2013a and I am trying to differentiate an expression in order to obtain a symbolic non linear differential equation. The expression has the following form:
syms t a(t) b(t) c(t) f=f(a(t),b(t),c(t))
where neither a(t), b(t) nor c(t) are known in their functional form, but the relation f(a(t),b(t),c(t)) is known in it's functional form. I wish to obtain:
df/da=g(a(t),b(t),c(t)) df/db=h(a(t),b(t),c(t)) df/dc=k(a(t),b(t),c(t))
I define the composite function f(a(t),b(t),c(t)), MATLAB recongnizes only a function of t f=f(t). I perform the following symbolic operations:
diff(f,a(t)) diff(f,b(t)) diff(f,c(t))
MATLAB does not recognize f as a composite function of a(t), b(t), c(t) and cannot perform the above differentiations. I cannot remove the time dependence a(t), b(t), c(t) since it will then be necessary to derive with respect to time.
Is some solution known for a problem of this type?
Thank you in advance.
Carmelo.
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