Microeconomics Project

Here is a (draft of a) project I am doing for a Microeconomics class at Empire State College.

Here is the project:

No Java 2 SDK, Standard Edition v 1.4 support for APPLET!!

Possible Problems

If the application doesn't come up at all, you will probably need the Java Plug-in. This is available (free) from Sun at http://java.sun.com/j2se/1.4.1/download.html. Click on the appropriate download link under the "JRE" column. This will get you to the correct place.
This page works with Microsoft Internet Explorer. If you are using Netscape Navigator, then click here.
Sometimes it appears to be taking a while to load. If you move the mouse over the blank area of the screen (between the two horizontal rules) it may speed things up a bit, but I have no idea why.
There can be problems with the graph display. If the graphs don't look right, hit the "Update" button, which should fix the problem.

Abbreviations

TC - Total Cost
TR - Total Revenue (= Q * P, both from the demand curve)
profit = TC - TR
AC - Average Cost (= TC / Q)
MC - Marginal Cost (= ΔTC / ΔQ)
MR - Marginal Revenue (= ΔTR / ΔQ)
AR - Average Revenue (= TR / Q)

Controls

There are two variables which can be changed:

slope

This is the slope of the demand curve, which is displayed as the AR, except when the slope is zero, when the AR is the same as the MR. The slope must be a valid (floating point) number and must be less than zero.

intercept

For a non-zero slope (a price maker), the intercept is the place the demand curve will cross the "Quantity" (x-axis) line. An increase in the intercept will shift the demand curve to the right. However, for a zero slope (a price taker), the demand curve doesn't cross the x axis, so in this case, it will be the y intercept, or price. May I suggest that for a zero slope, a low price (perhaps around 15) might be more appropriate, since the graphs do not adjust their scales automatically. The intercept must be a valid (floating point) number

The "Update" Button

Clicking the "Update" Button causes both graphs to be re-drawn. This is very quick. It can be used after slope or intercept is updated, or any time that the graph(s) are not properly displayed.

The Graph Scale

Please note that the "scale" of the graphs will change as values are changed. Both graphs will use the same "x" value, but it may change as the slope or intercept change. Each graph has its own value for the "y" scale. Again, they will change as the inputs change. Note that this is not a particularly sophisticated "dynamic scale", but it works pretty well for most "reasonable" values.