Function

2. FUNCTION
A function can be viewed as an input-output device. An input (or set of
input) is provided to a mathematical rule which transforms (manipulates)
the inputs into a specific outputs.
A function is a mathematical rule that assigns to each input value one
and only one output value.
Consider f(x) = 10 + 4x
Where f(x) = y
(y is a dependent variable and x is an independent variable).
Let x = 1, 2, 3 (input values or domain)
If x = 1 then f(1) = 10 + 4(1) = 10 + 4 = 14
If x = 2 then f(2) = 10 + 4(2) = 10 + 8 = 18
If x = 3 then f(3) = 10 + 4(3) = 10 + 12 = 22
in the above example input value of x =1,2,3 are the domain of the
function and the output value of 14,18 and 22 are the range of the
function.