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(dy/dx) = (dy/du)(du/dx)

Caution:Notice that if (dy/du) and (du/dx) were quotients rather than expressions for derivatives, we could cancel thedu`s and make (5) into an identity. But we stree thatduhas not been defined as an entity, and consequently it is not legitimate to cancel thedu`s. Nonetheless, the resemblance between (5) and an algebraic identity makes it easy to remember.

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so, he`s saying that I can`t cancel out the du`s, because they are not quotients, but expressions for derivative..

but I think that they can be canceled out!? is that true?

and yes they are expressions for derivative, but also they are quotients..

and I understand that we need them, and it would be meaningless to cancel them..

its just that I think he`s giving me wrong information when he said that I "can`t cancel them out" because "they are expressions for derivatives"

Am I wrong?

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# A quotation then a question

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