# Math Help - domain and range

1. ## domain and range

would the doman and range of

f(x)= square root of x

and

f(x) absolute value of x

be both ( sideways 8 , sideways 8 ) ???

2. Originally Posted by rj2001
would the doman and range of

f(x)= square root of x
the domain is the set of x values for which the function is defined.

what x's work here?

the range is the set of y values for which the function is defined. what is the range of possible outcomes of the function above?

f(x) absolute value of x
follow the same hint above, what do you get?

3. - sideways8 < x < sideways 8

im forgetting the x and y in between?

got it thanks

4. Originally Posted by rj2001
- sideways8 < x < sideways 8

im forgetting the x and y in between?

got it thanks
umm, no you don't

is that your answer for the first question? if so, that's wrong

Hint: you cannot take the square root of a negative number (this defines the domain)

5. thats infinity in case you dont know and its this ∞ which conveniantly happens to be alt + 236 or alt 8734 on most computers.

6. Originally Posted by ffezz
thats infinity in case you dont know and its this ∞ which conveniantly happens to be alt + 236 or alt 8734 on most computers.
i know what the user means by "sideways 8", he means infinity

i'm saying that's the wrong answer

7. umm, no you don't lol

domain x > 0 range [ 0, ∞ ) ??

domain ( - ∞ ,∞) range [0 ,∞) ?

8. so would f (x) = x^2 +3 be

domain
[-3 , 3)

range
[0 , ∞)

????

9. Originally Posted by rj2001
umm, no you don't lol

domain x > 0 range [ 0, ∞ ) ??

domain ( - ∞ ,∞) range [0 ,∞) ?
Close. The domain of $\sqrt{x}$ is $x \geq 0$, or $[0, \infty)$. (You can take the square root of 0, right? So it's in the domain.) You have the range correct.

You have the absolute value function's domain and range correct.

-Dan

10. Originally Posted by rj2001
so would f (x) = x^2 +3 be

domain
[-3 , 3)

range
[0 , ∞)

????
Is there any restriction on squaring a number? And what is the lowest value of your function? (Hint: it isn't 0.)

-Dan

11. Originally Posted by rj2001
so would f (x) = x^2 +3 be

domain
[-3 , 3)

range
[0 , ∞)

????
or okay so this would be domain all real #s ?>?

range greater or equal to 3?

12. Originally Posted by rj2001
or okay so this would be domain all real #s ?>?

range greater or equal to 3?
Yup!

-Dan