I have question regarding to product rule.
We know that derivative of y with respect to x is:
Now I'm trying to understand the proof of product rule:
to simplify notation:
Ok, now to proof:
we know that so we can substitute this with respected to u and v in equation and get:
Now to do some algebra we get:
And we know that
so finally we substitute u' and v' to the equation we get:
How i can get rid of since this is some error in my proof.