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Jan 20, 2013 at 18:51 comment added Deane Yang Why can't you use essentially the same definitions and proof used for the Hilbert space result?
Jan 20, 2013 at 18:30 comment added Chris @Deane Thanks for response. I did not consider weak derivatives of $f(t)$. But I don't know why $f'(t)$ would exist or why the formula you state is true (or false for that matter). Is it a standard result?
Jan 20, 2013 at 18:06 comment added Deane Yang Yes, I know. So why isn't $$\frac{d}{dt}\langle f(t),u(t)\rangle = \langle f'(t),u(t)\rangle + \langle f(t),u'(t)\rangle$$
Jan 20, 2013 at 17:33 comment added Chris @Deane by $f(t)(u(t))$ I mean $\langle f(t), u(t) \rangle_{V^*, V}$, the pairing.
Jan 20, 2013 at 17:30 comment added Deane Yang Why doesn't the usual product formula work?
Jan 20, 2013 at 17:28 comment added Chris @Liviu Apologies, $v(t) \in V$. I edited.
Jan 20, 2013 at 17:28 history edited Chris CC BY-SA 3.0
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Jan 20, 2013 at 16:47 comment added Liviu Nicolaescu $u'(t)\in V^*$ and $v(t)\in H$. How do you define $v'(t)(\; v(t)\;)$?
Jan 20, 2013 at 16:06 history asked Chris CC BY-SA 3.0