Table function

there's not really anything else to explain this example.

given some input (from the domain) to a function, the function must return exactly one output (in the range)

Since your table has one value (8) returning 2 values (4 & 6)  that table can't be describing a function.

The answer is simply applying the definition of a function.

maybe it would help you to think of it in normal "function" syntax rather than as a table.

f(4)  = 2
f(12) = 3

but

f(8) =6
f(8)=4

therefore f is not a function, because a function can't return 2 answers for one input.

Can you explain or a link little bit more about what is domain input and what exactly the range is?

Thanks. I think its a called parameters when we use these term in methods or functions in any programming language.

a parameter is a single value taken from the domain to be used in a function.

for example  I might have a function that operates on positive integers.

So f(10)  would be a legal function call.  10 is the parameter, not the domain.

the domain is the positive integers.

Thank You.