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September 17, 2014

September 17, 2014

Posted by **Ron** on Friday, January 27, 2012 at 4:21pm.

If f(x)=3x^2+7x+2, find f'(4) , using the definition of derivative.f'(4) is the limit as x--> ________ of the expression __________________. The value of this limit is _________________. I've got the first part that f'(4) is the limit as x--> 4, but I'm not sure what expression the second part is asking for. I can't find any examples and it's an online program, so I'm not sure if I got the answer and just didn't enter it correctly or I'm completely off. I'm pretty sure I can get the rest of the problem. Just need some help with the second part.

- calculus -
**Damon**, Friday, January 27, 2012 at 5:19pmwell, first I will giver the answer

6 x + 7

now

3 (x+h)^2 + 7(x+h)

3 x^2 + 6 x h + 3 h^2 + 7 x + 7 h

3 x^2 + 7 x + 2

---------------------------- subtract

6 x h + 3 h^2 + 7 h

divide by h

6 x + 3 h + 7

limit as h --> 0

6 x + 7 amazing

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