Hello, in coming up with a general form for finding the derivative of a product there is one step I do not understand.(adsbygoogle = window.adsbygoogle || []).push({});

if we let u, v and y be functions of x then:

dy/dx = u(dy/dx) + v(du/dx) + du (dv/dx)

From there we take the lim as dx -> 0 of each term and the textbook I am reading says:

"Now let dx -> 0. Then du -> 0"

I simply do not understand why it follows that du -> 0 because dx -> 0.

With this assumption however we are able to find the simplified general form:

dy/dx = u(dv/dx) + v(du/dx)

I applogize for not using the fancy math notation symbols. I have never used them before so I don't really know what half of them mean. I hope you guys can understand my question better than I can...

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# Differentiating Products

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