Question

Let f(x)=5·x2−2·x. Find (f(x+h)−f(x))/h if h≠0. Simplify your answer.

Answer 1

\[f(x) = 5x^2 -2x\]

Answer 2

Is that what you mean?

Answer 3

I don't think so. It didn't take that answer.

Answer 4

\[f'(x) =\frac{ f(x+h) - f(x) }{ h }\]
\[f'(x) = \frac{ [5(x+h)^2 - 2(x+h)] - (5x^2-2x) }{ h }\]

Answer 5

Thats because thats not the answer. Thats the orignal question.

Answer 6

\[f'(x) = \lim_{h \rightarrow 0} \frac{ [5(x+h)^2 - 2(x+h)] - (5x^2-2x) }{ h }\]

Answer 7

Now simplify

Answer 8

\[(5h^{2}-4x+2h) /2\] is this right?

Answer 9

then if you took the limit as h->0 it would be:

\[f'(x) = 10x-2\]

but i dont think u need that.

Answer 10

How did you get 10x+5h+2 ?

Answer 11

It didn't take either of those answers either /:

Answer 12

\[f'(x) = \lim_{h \rightarrow 0} \frac{ [5(x+h)^2 - 2(x+h)] - (5x^2-2x) }{ h }\]
\[f'(x) = \lim_{h \rightarrow 0} \frac{ 5(x^2+2hx+h^2) - 2x-h- 5x^2+2x) }{ h }\]

Answer 13

make sure you foil properly.

Answer 14

10x+5h-2 is correct.

Answer 15

I think i put +2 instead of -2 earlier

Answer 16

That was right. Thank you so much!

Answer 17

How do you do a testimony?

Answer 18

Go into my profile and write a testimony.. you might have to be a fan first..

Answer 19

Alright!

Answer 20

I don't see where to write a testimony. But I became a fan!

Answer 21

hmm i dont see where either.. oh well

Answer 22

oh i see it!

Answer 23

along the top of ur screen, where it shows ppl online.. click that.. hover over my profile until the little box pops up and clcik write fan testimony

Answer 24

sweet thanks, let me know if u have more questions!