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The precept
f (x) = ax
The Graph
The simplest example is: f (x) = 2x
In values, that means:
|
x |
- 1 |
0 |
1 |
2 |
3 |
4 |
5 |
|
y/ax |
½ |
1 |
2 |
4 |
8 |
16 |
32 |
That means that a number 2 to the power of an x-value
makes the y-value. If the y-value is given and the x-value (is 2|4 for
example), the reciprocal calculation must be used: the root! The second root
(the normal one) of the x-value = 2, and x = 3, the third root, so on and so
forth, from the respective y-value (in this example, it is the third root of
8 and the fourth root of 16).

Another (more difficult) example

The points 2|2 and 4|4 can be read off quite clearly.
Following the precept given above, the calculations would be following.

or: 
The function, in which a < 1
If the base is smaller then one (but also bigger than 0),
the values are similar to the values where the base is bigger than one, just
the reciprocal value of it!
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Base bigger than 1
Example: 2 |
Base smaller than 1
Example: 0,5 |
|
x |
y |
x |
y |
|
- 1 |
½ |
- 1 |
2 |
|
0 |
1 |
0 |
1 |
|
1 |
2 |
1 |
0,5 |
|
2 |
4 |
2 |
0,25 |
|
3 |
8 |
3 |
0,125 |
|
4 |
16 |
4 |
0,0625 |
|
5 |
32 |
5 |
0,03125 |
The Graph
This is what it would look like in the coordinate system
(to be exact, it is only a reflection on the y-axis):

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