3.1 Functions in Pictures
As we talked about earlier, a function is a relation between a dependant and an independence variable. This relation can be seen in four different ways:
 as a pattern
 with a value table
 as a graph in a coordinate system
 with a formula
We will, in this chapter, go through all the four ways, and we begin with patterns. For clarity’s sake, we will use the same examples that we used in chapter 1.
It costs 2 kr per minute to use a mobile telephone. To show you this in pictures isn’t difficult, and we show you with stacks of one crown coins. The independent variable is the number of minutes you use the telephone and the dependant variable is the total costs.
If you use the telephone for one minute, it costs 2 kr, two minutes cost 4 kr, three minutes 6 kr and so forth.
