Can I get help with this Cal 1 prob

- anonymous

Can I get help with this Cal 1 prob

- Stacey Warren - Expert brainly.com

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- katieb

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- anonymous

where is it?

- anonymous

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- anonymous

number 3

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## More answers

- anonymous

This is unfeigned cheating...

- anonymous

how so

- anonymous

I am not blind, I can see that you are taking an online test.

- anonymous

agree...

- anonymous

this is a quiz not a test we take tests in person

- anonymous

and we are allowed to get help on quizes as well as hw

- amistre64

:) what have you tried so far? maybe i can help iron it out

- amistre64

q3 looks greened out, which one of these are you actually needing help with?

- anonymous

I got the points of inflection but it said it was wrong on the last one i did it asks similar questions that generally have close to the same answer

- anonymous

3

- anonymous

that my first choice just not sure if it is correct would like someone to verify

- amistre64

i like working with product rule better that quotient rule; makes the mathing simpler to me

- anonymous

^

- amistre64

\[f(x)=x(9x^2-16)^{-1}\]
\[f'(x)=x'(9x^2-16)^{-1}+x(9x^2-16)'^{-1}\]

- amistre64

we need the 2nd derivative for concavity and infections

- amistre64

\[f'(x)=x'(9x^2-16)^{-1}+x(9x^2-16)'^{-1}\]
\[f''(x)=x''(9x^2-16)^{-1}+x'(9x^2-16)'^{-1}+x'(9x^2-16)'^{-1}+x(9x^2-16)''^{-1}\]
\[f''(x)=x''(9x^2-16)^{-1}+2x'(9x^2-16)'^{-1}+x(9x^2-16)''^{-1}\]

- amistre64

can you sort that out?

- anonymous

yes

- anonymous

OK i think i got it

- anonymous

also i am completly confused on this one

- amistre64

should come out to this in the end

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- amistre64

with that mess .... we find the zeros for top and bottom to test out

- anonymous

Yea thats what i got on that one

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- anonymous

How do i do number 6 though completly confused.

- amistre64

you get to the second derivative :)

- amistre64

f(x) = cx^2 - 3x^-2
f'(x) = 2cx +6x^-3
f''(x) = 2c -18x^-4

- anonymous

why did i have to post to this question lol notification crazy going on right now

- amistre64

now when x = 4, this ideally should equal 0

- anonymous

ok

- amistre64

f''(4) = 0 = 2c - 18/4^4
18/4^4 = 2c
9/4^4 = c

- amistre64

4^4 = (2^2)^4 = 2^8 = 256 i believe

- anonymous

then wat do i do after that

- amistre64

you compare c = 9/256 with the answer options and see what matches ......

- anonymous

ok cool i can do that

- amistre64

lol

- anonymous

also do u know what they are asking for this question

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- amistre64

im sure that i do

- amistre64

do you recall what a derivative (f') tells us about a function?

- anonymous

whether is conclaves down or not right

- amistre64

close, thats f'' the 2nd derivative
f' tells us the slope of the tangent line to any given point

- amistre64

so the graph of a derivative is negative when the slope at a point is negative; 0 when we reach a min or max or sometimes an inflection, and postive when the slope is increasing

- anonymous

oh ok see we havant really gone over how to get slopes from the graphs

- anonymous

how can i do that

- amistre64

im sure they give you options to choose from ....

- anonymous

oh im sorry i dint let u see the options let me reload it.

- anonymous

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- amistre64

|dw:1333414190749:dw|
the slopes should map out something like this

- anonymous

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- amistre64

|dw:1333414268730:dw|

- anonymous

that looks like A

- amistre64

umm, no further down; looks rather like an M

- amistre64

|dw:1333414363164:dw|

- anonymous

M theres no m lol

- amistre64

the graph "LOOKS LIKE" an M

- anonymous

Maybe c then

- amistre64

"M"aybe ;)

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- anonymous

one more question do you know to to find the conclave with the intervals

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