Enter a function f (x) into the text input field
marked "f (x)=".
(Example:
f (x)=x^{2})
Click the "Graph" button
(this button also refreshes the graph)
Enter a value for c
(Example:
c=1)
-- this can be done either of two ways:
Enter the value directly into the text input field marked
"c=", and click the "Graph" button.
Use the mouse to click and drag the
red point on the graph
-- this point takes its horizontal position from the mouse position,
and follows the graph of f (x); the horizontal position
gives the value of c
Enter a value for x
(Example:
x=2)
-- this can be done either of two ways:
Enter the value directly into the text input field marked
"x=", and click the "Graph" button.
Use the mouse to click and drag on the graph, anywhere except
the position of
the red point on the graph
-- the horizontal position of the mouse, shown by the vertical
blue line,
gives the value of x.
The "Point Zoom" button has an effect similar
to the "Zoom In"
button under the graph, but uses the
red point on the graph as the center of the new graph
region, so that
the "Point Zoom" button requires only one mouse
click, on the button itself, to enlarge the graph
(unlike the "Zoom In" button, which requires a
second click on the graph to determine the center point of the
new graph region)
To erase the graph and all input fields, click the
"Clear" button
The text input field for f (x) can accept
a wide variety of expressions to represent functions, and the
buttons under the graph allow various manipulations of
the graph coordinates.
The text input fields for c and x can accept real numbers
in decimal notation.
Examples
Other Notes
The values of c and f (c) are indicated
in the graph by
orange lines, with the red
point in the graph shown at the point (c,f (c)).
The values of x and f (x) are indicated
in the graph by
blue lines.
The table shows values of f (x) for x starting
at the given value and approaching c -- in particular, the
values x, c+(x-c)/2,
c+(x-c)/4, etc.
These values are indicated in the graph by
green lines.