Talk:Product rule (calculus)

Thanks, Anome. But if we have separate "formal" proofs that:

a) As &delta;x -> 0, &delta;y/&delta;x -> dy/dx (what I have called "differentiation from first principles") b) The limit of a product is the product of the limits, and vice versa (what I have called the "product rule for limits")

then does that make the proof count as a formal one? Kidburla2002.

The justification is informal, because it uses infinitesimals in an informal way: it works under most reasonable assumptions, but what about unreasonable ones? To do it formally, you can either use limits formally (with &delta; - &epsilon; type stuff), or a formalised system of infinitesimals. The Anome

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Why was this moved? What is going at Product rule? -- Tarquin

I am not aware of any other product rule, so a disambiguation like product rule (calculus) is unnecessary and I will move back to product rule. AxelBoldt 19:54 18 Jun 2003 (UTC)

The Product Rule is a proper name Pizza Puzzle