Question

Let f(x)=4x^2+3. Evaluate

lim h -> 0

(f(-3+h) - f(-3)) / (h)

Answer 1

Should both of those 3's in the last line not be the same sign?

Answer 2

Just fix it here, it's fine.

Answer 3

Finding the derivative?

Answer 4

It says evaluate and that's it. I assumed the answer would be 8 but it is not. I'm not sure what those threes are for.

Answer 5

Well f'(x) =8x, right?

Answer 6

yep

Answer 7

Hmm, does latex work?

Answer 8

The equation and drawing tools don't work, if that's what latex is.

Answer 9

Well if you're looking for the derivative, I can show ya how to get it, just give me a moment~

Answer 10

I'm just supposed to find what the limit is

Answer 11

This is the definition of the derivative f'(-3) evaluated at x=-3. That tells some of us the answer. Otherwise, carry out the operations [4(x+h)^2+ 3] -[4x^2 + 3}/h and let h go to zero,
after the denominator cancels to 1.

Answer 12

So the answer is 1?

Answer 13

They may just know it as a limit, although they are looking for the derivative.

Answer 14

Ah answer is -24. Thanks. Didn't realize you could take the derivative and then plug in -3.

Answer 15

answer should come out to -24, but you need to derive it

Answer 16

Awe, I already derived.. did all that work for nothing >_>

Answer 17

A medal for the work.

Answer 18

Thank you c: