Question

really need help with this question

Answer 1

\[3\]

Answer 2

oops

Answer 3

sorry

Answer 4

it ok

Answer 5

but can u help me andrew

Answer 6

@perl

Answer 7

@jigglypuff314

Answer 8

First find the first derivative :)

can you do that? and what would you get?

Answer 9

3x^2+18

Answer 10

oh wait...
hmmm
are you sure that is the proper function?

Answer 11

yes.

Answer 12

ok :/

Critical Points are when the first derivative is equal to 0

Answer 13

3x^2 + 18 = 0

does x equal any real numbers?

Answer 14

i think it does

Answer 15

then what would x equal?

Answer 16

i thnik 9 im nt really sure

Answer 17

3x^2 = -18
x^2 = -6

a squared number cannot equal a negative number (without being imaginary)
therefore there are no real values of x
so there are no Critical Numbers

Answer 18

ok that make sense i see how you got that .

Answer 19

but how do you determine when a interval is increasing or decreasing my teacher never thought that

Answer 20

really confused

Answer 21

interval is increasing when the derivative is positive
interval is decreasing when the derivative is negative

Answer 22

so there is no increase since we got negatives when we did the derivatives

Answer 23

not quite ^_^
the "no critical points" that we got just means that there are no changes from positive to negative or negative to positive
(it means that the function is either always increasing or always decreasing)

so just plug in a random number (like 0) into the derivative
3x^2 + 18
and tell me if you get a positive number or a negative number :)

Answer 24

wouldn't it be positive

Answer 25

that's right!

Answer 26

so it would Always be Increasing :)

Answer 27

but can it be decreasing at the same time

Answer 28

hmm no, I don't think so :)

Answer 29

so how do you know when it decreasing

Answer 30

if the number was negative, it would be decreasing
but that never happens

Answer 31

so in this problem would it only be increasing ?

Answer 32

yes :)

Answer 33

how would i determine the relative extrema

Answer 34

:/
relative extrema happen at the critical points
which we don't have

Answer 35

hank you for the help really appreciate. Can you help me with another question

Answer 36

thank

Answer 37

sure