Assignment 12

Jonathan Lawson

This exploration will look at spreadsheets and how they can be used within a mathematics classroom.

The spreadsheet can be a very easy tool to use to evaluate functions at specific x- and y-values and to help plot graphs.  This example will plot two different graphs.


y = x2 - 5x + 3 and y = (x - 3).5

1	-1	2

2	-3	2.236067977

3	-3	2.449489743

4	-1	2.645751311

5	3	2.828427125     

6	9	3

7	17	3.16227766

8	27	3.31662479

9	39	3.464101615

The first column of values are the x-values, the second column of numbers is for the first equation, and the third column of numbers is for the second equation.  The first equation is the blue function on the graph and the second equation is the purple function on the graph.

We can also use the spreadsheet to estimate values of certain charts if certain values are missing.  The next example shows data from a lumber industry, giving the approximate number of board feet of lumber per tree in a forest of a given age.  Even though data is missing we can estimate a function that would fit the data and be able to approximate certain values we do not know.


Age of Tree     100s of Board Feet
20 1
40 6
80 33
100 56
120 88
160 182
200 320

We can see that the graph is missing values, but with Excel, we can graph an approximate graph and try to figure out the missing values.

This is the graph that was interpolated by Excel.  Excel can also create a funcion of best fit.  I chose a second degree polynomial and Excel created this new function on the same graph and also created the equation for this line of best fit.

From this equation we can approximate values that were missing in our original chart.