Question

Show that the equation has a root in the given interval:

3x^3-2x^2+5x+4=0 [-1,0]

The book I have explains nothing...

Answer 1

We would have to factor it into is baser parts;

like 12 factors in 4 and 3

Answer 2

we can try to find a way to group it into parts that would work; but thats as much trial and error as my way :)

Answer 3

One method is to solve the equation for -1 and then for 0 and if there is a switch in signs; then it crosses the axis

Answer 4

who hs gmail

Answer 5

https://docs.google.com/document/d/1wPX_UwJrMAKjHc4j4mLkHwrL0rTr8ySI0m9u1KxxX2E/edit?hl=en&authkey=CMa9-_EO&pli=1#

Answer 6

go to that

Answer 7

do f(-1)
and do f(0)
if one is positive and one is negative then there is root on the interval -1..0

Answer 8

like this example

Answer 9

who `has gmail

Answer 10

http://uk.answers.yahoo.com/question/index?qid=20110324085500AAVlcai - This link will have the answer.

Answer 11

Okay, i'm with you

Answer 12

amistre pz go tothis link https://docs.google.com/document/d/1wPX_UwJrMAKjHc4j4mLkHwrL0rTr8ySI0m9u1KxxX2E/edit?hl=en&authkey=CMa9-_EO&pli=1#

Answer 13

Use the Intermediate Value Theorem to check for the existence of zeros (like myininaya said). If f(x) is continuous on [a, b] and if f(a) and f (b) are nonzero and have opposite signs, then f(x) has a zero in (a, b).

Answer 14

amistre plz go to this link https://docs.google.com/document/d/1wPX_UwJrMAKjHc4j4mLkHwrL0rTr8ySI0m9u1KxxX2E/edit?hl=en&authkey=CMa9-_EO&pli=1#

Answer 15

3(-1)^3-2(-1)^2+5(-1)+4 = ??
-3 -2 -5 +4 = -6

3(0)^3-2(0)^2+5(0)+4 = +4


Since -6 and 4 differ by "sign" the function has to cross the xaxis at some point in the interval between [-1,0]

Answer 16

Wow, I sure wish the book explained this stuff.

Answer 17

ammmmmmmmmmmmmmmmmmmmmmmmmmistrrrrrrrrrrrrrrrrre6444444444444444444444444444444

Answer 18

mary; please do not disrupt other peoples learning environment. If you do not have anything to contribute to the question at hand, please dont comment... thank you.

Answer 19

:)

Answer 20

but plz go to this link come on https://docs.google.com/document/d/1wPX_UwJrMAKjHc4j4mLkHwrL0rTr8ySI0m9u1KxxX2E/edit?hl=en&authkey=CMa9-_EO&pli=1#

Answer 21

email it to me, because it doesnt come out on my end....

Answer 22

whats your gmail

Answer 23

Jenn: Does that explanation make sense for you?

If you start on one side of the road and end up on the other side; youd have to have crossed the road at some point right?

Answer 24

same as it was last time :) tony031172@gmail.com

Answer 25

Yes, it makes more sense. This one is not as bad as the other one you helped me with.

Answer 26

plz check your mail now

Answer 27

lol...not as many chances to mess it up ;)

Answer 28

ok

Answer 29

Too funny..i have several more of those as well, so i'll try it

Answer 30

If I do them, will you let me know if the answer are right? Again,please..i can post them again too if you'd like

Answer 31

mary; the assassination of lincoln again? no thnx :)

Answer 32

We all can check ;)

Answer 33

Great...thank you so very much.

Answer 34

there no I in team, but there is an atem..and meat... and ate, tea eat, met, and other useful yet trivial words :)

Answer 35

i need you to help me on google doc

Answer 36

i needdd your hep

Answer 37

mary: helps is the operative word there. I am good at math, lincolns assassination, while it was a long time ago, still happened a few years before me :)

Answer 38

but plz go to gmail

Answer 39

its blank....

Answer 40

i nived you to my google doc

Answer 41

amistre why you left

Answer 42

so mean ou can help me an dget this done