Differential wrt qDot(t)

    syms t_1(t)
    f = sin(t_1) + cos(t_1) 
    diff(f, t) % Is Ok 
    diff(f, t_1) % should give us = cos(t_1)-sin(t_1), but we get error:

"Error using sym/diff Arguments, except for the first, must not be symbolic functions."

How should we calculate this in matlab?

Answer 1

[Ngoc Thanh Hung Bui]

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