Question 135933
What is the difference between domain and range? Describe a real-life situation that could be modeled by a function. Describe the values for x that may not be appropriate values. A function could, for example, indicate the amount of bone strength (y) in a living human body over time in years (x). It would not make sense to look at negative years, because the person would not yet be born. Likewise, looking beyond 100 years might not make sense as many people do not live to be 100.
---------------------
If you have a rule for a function (like y = 3/(x-5)) 
the domain is the set of Real Number values that x may have:
the range is the set of Real Number values that y may have.
Domain for my example is "All Real Numbers except x=5"
Range for my example is "All Real Numbers".
-------------------------------------------
The example you gave might be bone strength = 3*(1/2)^(years)
or y = 3*(2)^x where x is the age of a person.
Domain could be: 0 < x < 110
Range would be : 3 < y < 3*(1/2)^110
--------------------------------------------
Cheers,
Stan H.