This Geogebra file shows dynamically how the graphs of the sine, cosine and tangent functions change as the parameters in their equations are changed. Thanks to Greg Bland for sharing this very visual activity.

Geogebra is a powerful FREE dynamic geometry program. You can download it from
http://geogebra.org

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

Sine Box
http://www.ies.co.jp/math/java/trig/sinBox/sinBox.html

Cosine Box
http://www.ies.co.jp/math/java/trig/cosbox/cosbox.html

Tangent Box
http://www.ies.co.jp/math/java/trig/tanbox/tanbox.html

A highly effective interactive animation illustrating the sine and cosine graphs formed by rotating a point around the unit circle.
http://www.yenka.com/freecontent/item.action?quick=je#

This interactive animation shows the effect of adding a constant to the function.
http://www.yenka.com/freecontent/item.action?quick=ji#

This interactive animation shows the effect of multiply the function by a constant a where a >= 0.
http://www.yenka.com/freecontent/item.action?quick=ot#

This interactive animation shows how altering b in the function
y = sin(bx) changes the frequency/wavelength.
http://www.yenka.com/freecontent/item.action?quick=ou#

The powerpoint is digital and the activity is interactive. The two powerpoints are very well done - clear and profesional looking. The activity is nicely thought-out. Great job, Pam!

Powerpoints
http://www.geocities.com/pamburke74/LawofSines.ppt
http://www.geocities.com/pamburke74/AmbiguousCase.ppt

Activity Sheet
http://www.geocities.com/pamburke74/ToothpicksandPowerPoint.pdf

This animation from Lou Talman shows how a point moving around the unit circle generates the tangent function.
http://clem.mscd.edu/~talmanl/HTML/TangentCurve.html

This animation from Lou Talman shows how the sine curve can be constructed from the definition of the sine function as the y-coordinate of a point on the unit circle.
http://clem.mscd.edu/~talmanl/HTML/SineCurve.html

This animation from Lou Talman shows how a point moving around the unit circle generates the tangent function.
http://clem.mscd.edu/~talmanl/HTML/TangentCurve.html

This Quicktime animation from Lou Talman shows how the sine curve can be constructed from the definition of the sine function as the y-coordinate of a point on the unit circle.
http://clem.mscd.edu/~talmanl/HTML/SineCurve.html

A lovely Geogebra applet that graphically shows how the sine and cosine functions are generated from the unit circle. From The Lawrenceville School Mathematics Department Web Resources.
http://mathplotter.lawrenceville.org/mathplotter/mathPage/sine.htm