Your age is a linear function (of time).
Rational function can be used in real life in modeling multi-person work problems.
If you are asking about periodic function in the real world, than there are millions of examples. The first one that comes to mind are the sin and cos functions. These are used in almost every field of science.
Unless you are an electrical engineer or a math teacher, every number you will ever use in a real world situation will be a real number.
The diagonal of a unit square, for example, is radical(2).
what is the study of the design, form and function of objects in the real world
The basic idea is to represent the relationship between two variables as a function. Many problems in physics, chemistry, etc. use common functions (such as the square function, the square root function, the exponential function), or more complicated functions.
A cubic function can be used to represent the volume of a 3-dimensional object, or can be used to model a position of a certain unit.
the number of students depnds upon the classroom
You cannot. The function f(x) = x2 + 1 has no real zeros. But it does have a minimum.
A real world example of a cubic function might be the change in volume of a cube or sphere, depending on the change in the dimensions of a side or radius, respectively.
Well, since there is no such thing as a sphare in the real world, it is a bit hard to tell what it can or cannot use.
use a absolute value to represent a negative number in the real world
use to stop aids
Yes
use a absolute value to represent a negative number in the real world
you wouldn't