Use the interactive
display below. Move the points on the blue line or the two orange points on the
x axis.
All the values you pick out on the x axis
are called the domain
The values on the y axis that are therefore
picked out are called the range.
Observe how choice of domain affects the
range
Summary
To be absolutely precise, whenever you define a function,
for example f(x) = 17-3x, you should also define the domain for which it is
valid. If no domain is mentioned, this will probably mean that the function is
assumed to be valid for all values of x.
