Question

A doctor who is treated a heart patient wants to presicribe medication to lowere the patients blood pressure. The body's reaction to this medication is a function of the dose admininistered. If the patient takes x milliters of the medication, his blood pressure should decrease by r=f(x) points where

f(x)=3x^2-1/3x^3

what values of x make sence for this function

Answer 1

can u please help

Answer 2

Hmm.. I would say find the min value, and would that give you the x value? that would make the most sense?

Answer 3

i got 9 and 0

Answer 4

Okay, Im not sure I understand the question, sorry o.O
Because at x=0 f(x) =0 as well. I believe. I don't think that helps in anyway. Sorry

Answer 5

y = 3x^2-1
------- this?
3x^3

Answer 6

Ohhh. I didn't realize that was division. haha

Answer 7

sorry, but i dont know enough to help you out

Answer 8

amitre is that the answer

Answer 9

no thats a question about the problem :) is that the question at hand?

Answer 10

Any value greater than 0 would make sense. right..

Answer 11

no its what values of x make sence for this function

Answer 12

i think we want the maximum for f(x) so that his blood pressure reduces the most right?

Answer 13

well, any values of x will work except for x=0

Answer 14

i think we are looking for domain
?

Answer 15

y = 3x^2-1
------- is this the function we are working with?
3x^3

Answer 16

yes

Answer 17

then lets see where this function is increaseing and decreasing for x

Answer 18

Domain should be any value greater than 0. But I don't think its that simple.

Answer 19

no amistre has got it

Answer 20

nned function to be decreasing, or blood pressure is not decreasing

Answer 21

the 1st derivative is:

3x^3(2x) - 9x^2(3x^2-1)

-21x^4 +9x^2
-------------
9x^6

Answer 22

when the derivative is zero we get the highes and lowes of it;

Answer 23

-3x^2 (7x^2 -3) = 0 when x = 0 and...

sqrt(12)/14 = sqrt(3)/7 the only value here that makes sense is sqrt(3/7)

Answer 24

now is it a high or a low :) or an inflection point

is there an answer key for this to determine if we are doing it right :)

Answer 25

no ther isnt

Answer 26

3x^2-1
-------
3x^3


3 sqrt.3/7^2-1
--------------
3 sqrt.3/7^3


-40/49
-------------- thats a negative number so id say its not going to be that point :)
9/49 (sqrt.3/7)

Answer 27

lets see what the roots are if any to this equation

when 3x^2-1 =0

3x^2 = 1

x^2 = 1/3

x = sqrt(1/3) = sqrt(3)/3 is a zero

Answer 28

so that is the answer

Answer 29

0.577 is a root

Answer 30

dunno; still running tests in my head :)

Answer 31

ok its okay

Answer 32

can u help me with one more that is not realted to this

Answer 33

pomblem

Answer 34

please

Answer 35

http://www.wolframalpha.com/input/?i=%283x^2-1%29%2F%283x^3%29 is what we get for a graph

Answer 36

its only effective after x=sqrt(3)/3 and peaks at x=1

Answer 37

ok but can u help with anot

Answer 38

i can try :)

Answer 39

ok
it poynomials are u good at that

Answer 40

i can be at times lol

Answer 41

Find the first three terms in asending powers. (Do not compute the entire product)

(1-2x^2-x^4)(4+x^2-2x^4)

Answer 42

4 -7x^2 -8x^4

Answer 43

thats the answer