Question

Limit definition of derivative help

Answer 1

use the limit definition of the derivative to find f ' (x) for f(x)= x2 + 3x + 1

Answer 2

i know the answer, but i can't do it with the limit definition T_T

Answer 3

i know its 2x + 3, but how? with the limit definition...

Answer 4

Which definition are you familiar with? \[\Large \lim_{x \to x_0} \frac{f(x)-f(x_0)}{x-x_0} \]?

Answer 5

yeah, polynomial first principals are fairly straight forward

Answer 6

Some have a slight abbreviation of the above definition \[\Large \lim_{x \to x_0} \frac{f(x)-f(x_0)}{x-x_0} \iff \lim_{h \to 0 } \frac{f(x_0+h)-f(x_0)}{h} \]
I prefer the left one, for both, just plugin and try to simply as good as possible, since you know the result already you won't face many problems.

Answer 7

i found the answer, but ill give medal anyways.

Answer 8

very good! :)