Question

Find the indicated derivative. Assume that all vector functions are differentiable.

(expression in next post)

Answer 1

\[\frac{ d }{ dt }(r_{1}(2t) + r _{2}(\frac{ 1 }{ t }) )\]

note that (2t) and (1/t) are r AT (...) and this is not multiplication.

Answer 2

unless we know what r(t) is, all we can do is use chain rule
\[\rightarrow 2r_1'(2t) -\frac{1}{t^{2}}r_2'(\frac{1}{t})\]

Answer 3

That is all I wanted actually!

But I don't see how using the chain rule means multiplying by the derivative of the input.

Answer 4

Nevermind, I understand XD

Thanks!

Answer 5

yw :)