My teacher dun give me the Proof for Product Rule and Quotient Rule. She just asked me memorize the technique. Smart bros, pls guide me. I will also ask questions too. thanks

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- Aug 23rd 2010, 12:45 PMstupidguyProof for Product Rule and Quotient Rule
My teacher dun give me the Proof for Product Rule and Quotient Rule. She just asked me memorize the technique. Smart bros, pls guide me. I will also ask questions too. thanks

- Aug 23rd 2010, 01:34 PMChris L T521
We resort to the limit definition of the derivative to figure this out.

.

Now, we add "zero" to the numerator, particularly in the form of .

Thus, we have .

Splitting into two different fractions, we get .

We now see that we have .

Does this make sense? Do you think you can derive the quotient rule? It can be done in a similar fashion. - Aug 23rd 2010, 09:20 PMSoroban
Hello, stupidguy!

Here's the Quotient Rule.

We have: .

. . and we want: .

In the numerator, subtract and add

. . . . . . . . . . . . .

Divide by

Take the limit:

. .

Therefore: .

- Aug 24th 2010, 02:30 AMstupidguy
- Aug 24th 2010, 02:35 AMstupidguy
thanks to both of you. hopefully, I can help others with the knowledge i learnt.