Question

help another one:(

Answer 1

its wrong:(

Answer 2

wait, is that a derivative?

Answer 3

yes:(

Answer 4

First you need to find p' given what p is

Answer 5

p=f(x)g(x)
what is p'?

Answer 6

hint: use product rule

Answer 7

idk:(

Answer 8

You don't know product rule?

Answer 9

(uv)'=u'v+uv'
is product rule
u=u(x) and v=v(x)

Answer 10

yes i do the formula to find derivatives right?

Answer 11

but i don't know how to work with derivatives

Answer 12

So if p(x)=f(x)g(x)
then p'(x)=f'(x)g(x)+f(x)g'(x)
you are asked to find p'(4)

Answer 13

so this means you will need to know f'(4), g(4), f(4), and g'(4)

Answer 14

what is f(4) ?

Answer 15

just plug in after that?

Answer 16

3

Answer 17

f(4) is 3?

Answer 18

g(4) is 3

Answer 19

I think you looked at wrong function
so what is f(4)

Answer 20

f(4) is 7

Answer 21

ok f'(4)=?

Answer 22

you just need to know the slope at x=4 of f

Answer 23

just find the slope of that line going from x=4 to x=6

Answer 24

use the slope formula
\[f'(4)=\frac{f(6)-f(4)}{6-4}\]

Answer 25

oh i see!!!!! but then it would equal to 0

Answer 26

no

Answer 27

like she said above

Answer 28

f(6)=?

Answer 29

how are you guys getting f'(4) is 0?

Answer 30

i have no clue! i think i am looking at this whole function wrong

Answer 31

to find f(6) look a long the x-axis for 6 then scroll up until you see f's graph
what is the y that corresponds to x=6?

Answer 32

yes that is what i was doing, you asked for f(4) which is 3
but then you said that was wrong?

Answer 33

f(4) is not 3

Answer 34

now f(6) is 5

Answer 35

1?

Answer 36

for f(3)

Answer 37

f(6)=5 is correct
but f(4) is between 6 and 8

Answer 38

f(4)=7

Answer 39

f is labeled as the black graph
i think you looked at the blue graph

Answer 40

i idid that at the beginning

Answer 41

\[f'(4)=\frac{f(6)-f(4)}{6-4}=\frac{5-7}{6-4}\]

Answer 42

yep and you did again too

Answer 43

lol yes i saw

Answer 44

-2

Answer 45

just gave me a new problem since i got 1st one wrong, sorry!

Answer 46

we'll leave it for tomorrow if you like!

Answer 47

well you would need to find f(8) , g(8), f'(8) , g'(8)

Answer 48

You should be able to find f(8) and g(8) pretty easily
the trick to find f'(8) and g'(8)
is to think slope
find the slope of the line surrounding (8,f(8)) and (8,g(8))
You need to use two points on those lines to find the slopes of those lines

Answer 49

f(8) is 2?

Answer 50

you are getting the curves backwards again

Answer 51

okay give me a second

Answer 52

6

Answer 53

?

Answer 54

yes f(8)=6

Answer 55

and g(8)=2

Answer 56

now you need to find f'(8)
to do this just find the slope that (8,6) lies on

Answer 57

you need two points on that line

Answer 58

you already have one (8,6)
can you tell me another point that is on that line (in which (8,6) occurs)?

Answer 59

3,8?

Answer 60

(3,8) is on a different line part

Answer 61

This little thing I drew is the line we are looking at
we have one (8,6)
but (3,8) is not on it

Answer 62

you can use any two of those points to find the slope of that line