April 16, 2014

Homework Help: Calculus - need help!

Posted by NaNa on Thursday, October 11, 2007 at 1:09am.

Use the definition of the derivative to find f'(x)

1. f(x) 2x^2 + x - 1

Before the final step, my 'result' looked weird and I think I did something wrong in my arithmetic...someone correct me?

Here's my work...

lim [2(x + deltaX)^2 - (x + deltaX) - (2x^2 + x - 1)] / deltaX

near the end step:
lim [4x + 2deltaX - 2x^2 - 1] / deltaX


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