works, does it not?
How do I find the function rule for an exponential function?
The function values are like this:
x- -2 -1 0 1 2
f(x)- 1 2 4 8 16
I know the answer is f(x)= 4(2)to the x power
I don't get how to come up with the function rule.
I'm teaching from the book Glencoe Algebra 1 1997.
The problem was on a supplemental review I printed out from http://www.mcps.k12.md.us/curriculum...B%20review.pdf
and it was problem #2 c.
The answer key was at http://www.mcps.k12.md.us/curriculum...view%20KEY.pdf
I can't see anyplace in the text that I have that explains how to determine the function rule other than to study the data table or look at the graph. I can't find any instruction or practice on this so any help or a link to someplace to learn and practice finding the function rule would be appreciated.
Brett Taylor
Teacher- Tomlinson Adult Education Center
I am certified in math grades 5-9 and mainly teach adult GED students but I have a few credit math students.
Thanks-
Hello,
maybe the authors of the test are refering to the question 1.1.2.3 where a (very simple) general equation of an exponential function is mentioned. The coordinates of the points must satisfy this equation that means if you plug in the x and y-values the general equation becomes true:
[1]
[2]
Divide [2] by [1]:
Now plug in this value into [1]:
The function is completely decribed by:
A more general form of an exponentila function could be:
. That means you have 5 parameters. To determine these 5 values you need at least 5 points with their coordinates. The meaning of these parameters are:
a: A factor which describes the dilation(?) of the graph.
k: A factor which describes the dilation(?) of the graph.
t: Determines the horizontal translation.
c: Determines the vertical translation.