Question

Can someone explain "domain" and "range"? (When talking about functions

Answer 1

"Domain" is the set of all possible inputs. Any values that don't give you a nonexistent answer (division by 0, etc) when you plug them into the function.

"Range" is the set of all possible outputs.

Hope this helps!

Answer 2

could u explain a bit further... thanks :)

Answer 3

domain - the set of x "input" values of a function that produces a valid y
range - the y "output" values that correspond with given set of x values

Answer 4

Sure! What are you confused about? :)

Answer 5

OH thanks Hero! And Zxen too:)

Answer 6

You're welcome

Answer 7

do you have to have more than one x,y point to have a function?

Answer 8

I don't think a point by itself can represent a function....Well, I've never seen it....you would normally write f(x) normally represents some expression in terms of x, so it would have a certain amount of inputs and outputs.

Can you write a point in the form of an expression? I don't think so.

Answer 9

Nope. Most functions have more than one, but as long as each x value corresponds to one and only one y-value, it's a function. :)

Do you have a particular problem you need help with, or is this just general stuff?

Answer 10

So from my point of view, I'd say you can't represent a point as f(x). That being said, you can restrict values of x in a function.

Answer 11

new school, new math course :P
Want to see if I can do most of the problems by myself though. Those were just some terms that tripped me up.

Answer 12

logging off and returning to my books %0 Thanks guys!

Answer 13

Anytime! :D

Answer 14

You can have a function of only one point. A function is just a relational mapping of input values and output values where each input value is mapped to one (and only one) output value.

So for example the function:
\[f_1(x) = \cases{\begin{array}{ccc}4 & \text{if} & x = 1\end{array}}\]
Would be an example of a function which has only one element in its domain: {1} and only one element in its range: {4}. If you were to graph this function you'd just have that one point.

Since each element in the domain maps to only one element in the range, the relation satisfies the requirements of a function.