Question

I have a question on a limit function....

Answer 1

Let's hear it.

Answer 2

give me one sec. thanks

Answer 3

f(x+(delta)x) - f(x)/(delta)x lim as (delta)x approaches 0..... f(x) = x^2 - 4x

Answer 4

-4?

Answer 5

good amistre64 :)

Answer 6

all that verbiage to say; whats f'(0) lol

Answer 7

I'm getting stuck on the algebra...... I have 2x-4 for some reason

Answer 8

and when x = 0 what doe you get?

Answer 9

No, it's (delta)X

Answer 10

deltax = h; just say h

Answer 11

(delta)x goes to 0

Answer 12

ok

Answer 13

or if you wanna get really wild: delta x = partitional section of the distances from x to som interval that goes to zero; but h is simpler eh lol

Answer 14

si

Answer 15

f(x+h) - f(x)/h

Answer 16

(x+h)^2 -4(x+h)-(x^2 -4x) //h

x^2 +h^2 +2xh -4x -4h -x^2+4x//h

Answer 17

when the function is f(x) = x^2-4

Answer 18

I'm getting stuck with the 2xh

Answer 19

cancel the terms that cancel and get:

h^2 +2xh -4h//h

h + 2x -4 when h = 0 is 2x -4

Answer 20

the derivative of x^2-4x IS 2x -4

Answer 21

not taking derivatives yet....

Answer 22

your learning that the longway to get to the derivative just proves the shortcut methods lol

Answer 23

ok so 2x-4 is the limit?

Answer 24

oh yes, you are..

Answer 25

we are trying to find L

Answer 26

and yes, the lim would be 2x-4; since the lim as h->0 of f(x) is the definition of a derivative

Answer 27

OK thank you. I just wanted to make sure.