There is a mistake in your limit:

should be:

Do you now see why the result follows?

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- January 3rd 2009, 10:50 AM #1
## dy/dx question...

Hey all,

I'm getting ready for my first semester of Calculus and I'm a big dork so I'm actually interested in the subject.

Anyway I have a quick question: when differentiating I was taught by my trusty textbook to multiply by the conjugate using the difference quotient and so then after several calculations you end up with:

THEN for some reason you can get rid of the "h" in and you're left with .

Now I get how to do everything just fine, I just want to know why the "h" can just go away like that.

Thanks for the help!

- January 3rd 2009, 10:52 AM #2

- Joined
- Jun 2008
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- January 3rd 2009, 10:55 AM #3

- January 3rd 2009, 10:58 AM #4

- January 3rd 2009, 11:00 AM #5