Question

Help @Data_LG2

Answer 1

Problem #13

Answer 2

give me a sec.

Answer 3

Okay! Take your time.

Answer 4

*uses calculator first before actually working*

Answer 5

first thing to do, find the first derivative,

Answer 6

then the zeros of the first derivatives..

Answer 7

yes, then?

Answer 8

@Psymon .. another thread:)

Answer 9

How will you find critical numbers?

Answer 10

Im here.

Answer 11

Critical numbers are once you take the derivative, you set the derivative equal to 0 and solve for x.

Answer 12

Critical numbers are basically points where the function is undefined or where the slope is 0.

Answer 13

I know that. But doing that is difficult here in this problem

Answer 14

,using the zeros of the first derivatives, substitute it on the equation and you will get the critical numbers..

Answer 15

Show me.

Answer 16

did you get the first derivative of the function?

Answer 17

Yes

Answer 18

factor it..

Answer 19

You try. Factorization is the main problem

Answer 20

ok..

Answer 21

I'm only having problem with factorization. Other things i can do

Answer 22

http://www.wolframalpha.com/input/?i=factor+x^4%2B4x^3-330x^2-800x%2B12000
factor of the first derivative..

Answer 23

Ridiculous by hand.

Answer 24

right:) its too long and difficult

Answer 25

I remember seeing a student with a problem like this and the professor wanted them to actually use newton's method and then have the actual zeros to within .5 units. The numbers weren't as massive, but the task was still stupid. And they still had to do the rest of the derivative, inflection whatever crap.

Answer 26

@Psymon newton's method?? how to do that?

@mathsabc still there?

Answer 27

Yes. I was also trying once more

Answer 28

No simple way?

Answer 29

i don't think so..

Answer 30

It's a formula to approximate the zeros of a function.
\[x _{n+1}= x _{n}- \frac{ f(x) }{ f'(x) }\]
And once you get a result from that you use that result and repeat the formula. The first xn you choose has to be a reasonable guess of what the zero actually is. If you don't guess welll enough you could be going for a while. If you do guess well, you usually don't have to do more than 3 repetitions. Still annoying.

Answer 31

Yes, annoying again. huuuuufff... bad question..

Answer 32

did you open the link i posted?
lets stick with that factored form and get over it, is that ok??

Answer 33

I'm going. Got some urgent piece of work. Thank You for you help.