Questing about symbolic differentiation, inner derivative

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Hi everybody,
I am doing a project that requires alot of symbolic differentiation. I need to differentiate expression like cos(theta(t)) w.r.t t, is this possible with matlab? If so, how?
I know that I could easily do this with mathematica but I am also using simulink, so it would be easier just to use one software.
BR,
Per

Accepted Answer

Walter Roberson
Walter Roberson on 5 Feb 2014
Yes, the Symbolic Toolbox can handle that without difficulty. The syntax would go something like
syms theta(t) t
diff(cos(theta(t))

More Answers (1)

Per
Per on 5 Feb 2014
Walter,
Thank you for the fast answer. Can I extend this syntax to vectors of symbols?
BR,
Per
  1 Comment
Walter Roberson
Walter Roberson on 5 Feb 2014
You can differentiate a vector of expressions, but you cannot differentiate with respect to a vector. If what you are looking for is the partial derivatives then you can use the syntax
diff(F,var1,...,varN) differentiates F with respect to the variables var1,...,varN.
but you cannot use diff(f,[var1, var2, var3... varn])
What you can do in MATLAB is
varvec = [var1, var2, var3... varn]; %however it got built
T = num2cell(varvec); %convert to cell array
diff(F, T{:})
the T{:} syntax expands the cell array to become individual arguments to the call.

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