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# what is domain and range? watch

1. my teacher decided to flippin move me up to further maths next week so I need someone to help me understand this topic cause I'm far behind the rest
2. Answer depends what level this is.

You can think of the domain as the acceptable inputs and the range the possible outputs of those inputs.

By acceptable, I mean the element in the domain should map to an element on the rage; the function should be defined for that value.

E.g. y=1/x

Domain; x is any real number but 0
Range; y is any real number but 0

y=x^2
Domain: x is any real number
Range: y>= 0
3. They are part of functions

Domain are the x values that "map" the y values on graphs. Then range are for the y values that you can possibly have from the x values
4. (Original post by ima.hogg)
x
The domain of a function is the complete set of real values that can be inputted into the function for it to give a real output.

Where as the range of a function is the complete set of possible outputs of the function.

For example the graph of

Has a domain of x >= 2 because the value within the root cannot be less than 0 or the output wouldn't be a real number.

And it has a range of y >= 0 because a real value of a square root will never be negative.
5. (Original post by ima.hogg)
my teacher decided to flippin move me up to further maths next week so I need someone to help me understand this topic cause I'm far behind the rest
domain is the set of value that you can stick into a function and range is what comes out when you stick the domain into the function

for example f(x)=x² where so that domain is 0,2 so all the numbers including 0 and 2 i have defined as valid things you can stick into f(x) and to get the range you stick 0 and 2 into f(x) and see wat comes out in this case it's 0 and 4 so that's the range.

Or you can think of the domain as the x axis and the range as the y axis

so if you have the graph x² and the domain is 0 and 2 then you can look at the graph of x² between 0 and 2 and see what corresponding y values 0 and 2 give
6. ahh so if the question asks you to find the domain of f(x)=x², would the domain be all the real numbers because you can put any number into the function?
7. (Original post by ima.hogg)
ahh so if the question asks you to find the domain of f(x)=x², would the domain be all the real numbers because you can put any number into the function?
Yes indeed it would!
8. Thanks a lot everyone!!
It isn't as hard I thought it would be... or at least I hope so

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