Question

Which of the following could be an example of a function with a range (-∞,a] and a domain [b,∞) where a < 0 and b < 0? A. f(x)=√x-a+b B. f(x)=^3√(x-b)+a C. f(x)=-^3√x+a-b D. f(x)=-√x+b-a

(the root only covers the first two variables in each answer choice)

Answer 1

Kassia...quick question...

Answer 2

what?

Answer 3

Is it :\[f(x) = \sqrt{x-a+b}\] or

\[\sqrt{x} -a+b\]

Answer 4

for the first one...

Answer 5

in between it covers the first tw ovariables

Answer 6

Okay....yeah, I just saw what you wrote about the root covering the first to variables...thanks

Answer 7

any idea how to answer it??

Answer 8

Working on it

Answer 9

thanks!@

Answer 10

Apparently, an easier way to figure this out is by using actual numbers for a and b. They're both negative so, if a = -3 and b = -5....you can use that to help figure this out

Answer 11

Have you tried it yet, or do you want me to explain further using examples?

Answer 12

Kassia, what are you doing? lol

Answer 13

Kassia, are you there?

Answer 14

Okay, well, the answer is D

Answer 15

I can show you why...

Answer 16

sorry i had to make a copy, so i need to just plug in those variables and then i can get the answer?

Answer 17

sorry i had to make a copy, so i need to just plug in those variables and then i can get the answer?

Answer 18

sorry i had to make a copy, so i need to just plug in those variables and then i can get the answer?

Answer 19

Well,no, it doesn't exactly work like that. I'd have to explain it

Answer 20

This is more than just plug and play

Answer 21

First of all we not only do we need to choose numerical a and b, we also have to find an x in the appropriate range between b and infinity

Answer 22

And we have to test them all out, but there's an interesting twist to it.

Answer 23

It involves the cube roots. You can take the cube root of a negative number, but you can't take the square root of a negative number...

Answer 24

So when we test these out, we have to take that into consideration

Answer 25

So when we we're testing out the cube roots, we'll use x = -32 and x = 22

Answer 26

We're looking for an x, a, and b such that when we evaluate them, it will give us the appropriate range

Answer 27

We obviously can only use x = 22 for the square root functions so if you choose a = -3 and b = -5, you will see that the only thing that works is D