FITTING
TRIGONOMETRIC (COSINE FUNCTION) DATA APPLET
This
applet has two functions: First, it can be used to plot user supplied
data. It can also be used to test if a user supplied trigonometric (sine)
function (a function of the form y = a + b cos(k (x  c)) ) fits the
given data by plotting the function. Use it as follows:

The
sequence of operations must be as follows:

The
user must enter the data to plot in the DATA area. Though the
variables default to x (the independent variable) and y (the dependent
variable), they can be renamed. Renaming them will cause the graph
to be updated. The values are entered one per line. Error messages
will be displayed in the MESSAGES area if the data does not have
the correct format, that is if the data is not a number.

The
user can then plot the data by pressing the "PLOT DATA"
button

The
user supplies the coefficients defining the function to test.

The
user plots the function by pressing the "TRY" button.

The
buttons work as follows:

CLEAR
will clear the DATA area, the PLOT area and the MESSAGES area.

PLOT
DATA will plot the data as points.

TRY
will plot the trigonometric function corresponding to the coefficients
supplied by the user.

The
PLOT area (top, right) will show the plot.

The
MESSAGES area is used to communicate with the user. Errors will be
displayed there, for example if the number of values is not the same
for both variables. Information will also be displayed there.

