Question

Please Help with Pre-Calc Questions anybody please...?

For each of the following functions, identify any restrictions on its domain.

5. F(x) = cubroot of (x-2) +3
6. F(x)=log(x-5)+1
7.e^(x+4)+7

Is there any value of x that would cause this function to be undefined?
If there are restrictions on the domain, explain those restrictions.
If there are no restrictions, explain why that is.

Answer 1

well can you do cuberoot of any real number?
for example do you know the cuberoot(-1)=?
or the cuberoot(0)=?
or the cuberoot(1)=?

Answer 2

wouldn't it be -1?

Answer 3

yes
so you can do cuberoot(-1)=-1
so you can do cuberoot of negative numbers or even 0 or positive numbers right?

Answer 4

The cuberoot function is defined everywhere.

Answer 5

what about log
can you do log(0) or log(-1)?

Answer 6

right

Answer 7

it would be undef?

Answer 8

so you know you do log(positive) only

Answer 9

so you will have restrictions for the log function you have above

Answer 10

yes

Answer 11

you want x-5 to be positive

Answer 12

therefore you want x-5 greater than 0
so just solve x-5>0

Answer 13

so for the firs question i just say that it is undef at log(-1) and log(0)?

Answer 14

well it is undefined when the inside is negative or zero
so if you are looking where it is undefined instead of define
just negate x-5>0
and you have x-5<=0

Answer 15

? how would i answer the first question?im confused

Answer 16

I thought we already said yes to that question because you cannot do log(negative or zero number)

Answer 17

we can do log(positive number)
x-5 is positive when it is greater than 0
so you can find x such that x-5>0 by solving the inequality

Answer 18

srry i thought your most recent post was about the first question..

Answer 19

I'm confused.

Answer 20

I thought the first question is it undefined anywhere

Answer 21

just continue i understand now

Answer 22

hello?

Answer 23

hi

Answer 24

do you have any questions?

Answer 25

there u are

Answer 26

yes can u help me with the rest of them?

Answer 27

Do you know anything about e^x?

Answer 28

Do you know of any restrictions ?

Answer 29

for example does
e^(-7)
or e^(0)
or e^(8) exist?

Answer 30

can you raise positive numbers to a negative,0, or positive power?

Answer 31

srry i type slow

Answer 32

yes it comes out a decimal

Answer 33

ok e^x exists everywhere

Answer 34

you can also look at a visual and see this too

Answer 35

ok

Answer 36

so only one of the functions you listed has restrictions (or some place where it is not defined) over the real numbers

Answer 37

ok thank u i appreciate it

Answer 38

so you did understand cuberoot and exponential functions exist everywhere over the real numbers and has domain all real numbers
but log functions do have restrictions over the real number because you can only do log(positive numbers)

Answer 39

yes

Answer 40

now i do thank u

Answer 41

np