## "Old Faithful" Histogram

This applet teaches students in a very dramatic way how changing the "bin width" of a histogram can dramatically alter the shape of the histogram. Lesson: you should graph your data with a number of different bin widths and choose the one that you feel best represents the data.

http://www.stat.sc.edu/~west/javahtml/Histogram.html

## Completing the Square

Here are two versions of Completing the Square - a web page from NCTM and an ActivStudio flipchart.

Completing the Square web page
http://illuminations.nctm.org/ActivityDetail.aspx?ID=132

Completing the Square flipchart

## Virtual Slide Rule

An on-line slide rule. Brings back memories....
http://www.syssrc.com/html/museum/html/sims/javaslide/

Click on the title above to download the slide rule in an Activstudio flipchart.

## Derivative of y= x^2

Move the red dot on the parabola and the gradient function (a linear function) is graphed below it. Very neat. From Manipula Maths.
http://www.ies.co.jp/math/java/calc/x_diff/x_diff.html

This applet also draws the graph of the 2nd derivative.
http://www.ies.co.jp/math/java/calc/x_2nd/x_2nd.html

## Derivative of Sine and Cosine Functions

Move the red dot on the trig function and the graph of the gradient function is shown below. Very neat! From Manipula Maths.
http://www.ies.co.jp/math/java/calc/sin_diff/sin_diff.html

This applet also shows the graph of the 2nd derivative.
http://www.ies.co.jp/math/java/calc/sin_2nd/sin_2nd.html

## Surfing

A man is riding on the surf. We set f(x) as the curve of the wave . Observe the slope of the surfbord. The trace of the slope is the derivative of f(x). From Manipula Maths.

http://www.ies.co.jp/math/java/calc/doukan/doukan.html

## Changing the Border & Dividing a Quadrilateral

Changing the Border
This is a nifty puzzle whose solution is based on the area of a triangle. The land is divided into two parts (P and Q) by the border ABC. Redraw a straight border line passing through point A so that each of the areas does not change.
http://www.ies.co.jp/math/java/geo/tochia/tochia.html

This is a more challenging problem that is based on the same underlying concept.
http://www.ies.co.jp/math/java/geo/shi2to/shi2to.html

## Sine Box, Cosine Box and Tangent Box

Some wonderful animations that show the sine, cosine and tangent of angles on the unit circle.

## Sum of the Exterior Angles of a Polygon

This is a neat look-see proof that the sum of the exterior angles of any polygon is 360 degrees.
http://www.ies.co.jp/math/java/geo/gaikaku/gaikaku.html

## The Angle Sum of a Triangle

Move the triangle by dragging the red point. What did you find?
http://www.ies.co.jp/math/java/geo/san180/san180.html