# Calculus

posted by .

I'm doing graphs/domain/range of basic functions. I have three questions:

How do I find the domain and range of a function? (more preferably range...I'm okay but shaky on domain)
Ex: f(x)=1/(x^2)

Also, how do you write the domain and range with notation? Like when you use symbols like
(-infinity, 0) U (0, infinity)
Specifically, how do I write "All real #'s where x cannot equal..."?

One more thing: what does [[x]] mean? The symbol looks like two brackets very close together or something.

Thank you very much!

• Calculus -

Domain is the set of valid values as input to the function. In the particular example,
f(x)=1/(x^2)
x can take on all values except ±∞ and 0.
So the domain is (-∞,0)∪(0,+&infin)
which means that the domain can take on all values from (but excluding) -∞ to (but excluding) zero, and from (but excluding) zero to (but excluding +∞.
The range is the interval of possible values when the function is evaluated. In the particular example, the range is (0,+∞). The evaluated function cannot take on negative values as x is squared.

Numerous articles are available for the description of interval notation. Basically, an interval is described by the lower and upper limits, separated by a comma. If the lower limit is included in the interval, a square left bracket is used. If it is to be excluded, a praenthesis (round bracket) is used. The same goes for the upper bound (right bracket.) For example,
[5,+∞) ranges from and including 5 to but excluding infinity.
For more detailed descriptions, see:
http://en.wikipedia.org/wiki/Interval_(mathematics)
http://id.mind.net/~zona/mmts/miscellaneousMath/intervalNotation/intervalNotation.html
http://en.wikipedia.org/wiki/Domain_of_a_function

I have not come across the [[x]] notation. Please give more information or context of its use.

• Calculus -

Thanks for the domain and range info!

Regarding the [[x]] symbol, the function is simply y = [[x]]. There isn't a symbol like that on my calculator (TI-89).

I want to say that this may be the same as brackets, which I believe means absolute value. But what would be the difference between y = lxl and y = [x]?

I'm honestly not sure either...

• Calculus -

Sorry, I still don't have more information on [[x]]. If you have the answer or someone else has, please post and share the information.

## Similar Questions

1. ### Math (pre-calculus)

Hey! I have a domain and range question! I don't remember how to get these, can you help?
2. ### Algebra

23. The ___ axis represents the independent variable. X?
3. ### Math

You have 6 cups of sugar. It takes 1 cup of sugar to make 24 cookies. The function c(s) = 24s represents the number of cookies, c, that can be made with s cups of sugar. What domain and range are reasonable for the function?
4. ### math (2nd Try)

You have 6 cups of sugar. It takes 1 cup of sugar to make 24 cookies. The function c(s) = 24s represents the number of cookies, c, that can be made with s cups of sugar. What domain and range are reasonable for the function?
5. ### precalculus check immediately

suppoe f is a function with domain [1,3]and range[2,5]?
6. ### alg 1

Quadratic graphs and their properties: Identify the domain and range of each function: y = 4x^2 - 3 I have no idea how to find the range and domain. Would you please explain in detail how I can determine the domain and range in the …
7. ### algebra

Find the domain and range of the relation and determine whether it is a function?
8. ### Math

HELP PLEASE!!! I'm having some trouble with this question on my Maths hw. Any help is appreciated:) Identify the domain and range of the function. y=-0.25x^2 1. domain: (-oo, 0] range: (-oo, oo) 2. domain: (-oo, oo) range: (-oo, 0] …
9. ### Math

What are the domain and range of the function {(0, 2), (-2, 4), (2, 8), (1, 6), (-5, 0)}?
10. ### Math

What are the domain and range of the function {(0, 2), (-2, 4), (2, 8), (1, 6), (-5, 0)}?

More Similar Questions