# Domain and Range of functions

Could someone please explain to me what the range and domain of a function is and how to find them? I just don't understand what they mean
Thank You

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Mark44
Mentor
The domain of a function is the set of all valid inputs to the function. The range is the set of all possible outputs.

For example, if f(x) = 1/x2, the domain is all real numbers except 0. The range is all real numbers greater than 0.

D = {x in R | x $\neq$ 0}
R = {y in R | y > 0}

Domain is all the possible values that X could be
Range is all the possible values that Y could be

example: determine the domain and range of y= x^2

when u sketched the graph, you can see x could be anything, it keeps going forever there for D( -infinity, +infinity)

for y, however, you can see y never goes below x axis, the maximum value for y is just 0
therefore (0, +infinity), because y goes up forever.

But domain and range cant share a common number Can they?

Mark44
Mentor
But domain and range cant share a common number Can they?
Sure, why not?

HallsofIvy