Tuesday, December 31, 2013

Explore Dynamic Geometry in the New Year!

A GeoGebra design such as this would have a student confront the notions of circle, radius, vector, rotation, translation, and angular speed.

Why can't students learn the vocabulary first and all the fancy math details later?

Dynamic geometry can be an entrance into mathematics.

For more, see www.davemath.com

Monday, December 30, 2013

One circle and one pentagon....

Dynamic geometry can be the door of entry to higher mathematics if it can be the "hook" that captures a students imagination.
This was made in free GeoGebra. Click on tyhe image to get the actual geoGebra file behind it.
For more on dynamic geometry, visit www.davemath.com

Monday, December 23, 2013

Cause and effect

Since we spend a great deal of our lives claiming to causes of the effects we see, I would think it would not be too big a deal to describe the cause of the following path.
If you wish, you can click here to see a small web page about it.
Good luck!

Wednesday, December 18, 2013

Blog Error

Starting this morning, whenever I click the "design" link at the top of my main blog page, I get this error.
ERROR: Possible problem with your *.gwt.xml module file.
The compile time user.agent value (ie9) does not match the runtime
user.agent value (ie10). Expect more errors.

No matter what I have tried, the error persists. Does anyone have a clue about this?

Monday, December 16, 2013

Golden Arches: Parabolas or Not?

Click on the leftmost toolbar icon, then drag the 5 points to either the inside or outside edge of one of the arches. GeoGebra will show you what it gets. (The other tools are, in order,  for moving everything, zoom out, zoom in, and selecting a single item.) EXPERIMENT!!!
Note: You mat have to click in the space below to activate the graphic.

Sunday, December 15, 2013

Omega Unlimited: The Golden Arches ® Exposed!

This is a link to an older post by someone else. Tomorrow I will post a page that will let you test this theory for yourself. Omega Unlimited: The Golden Arches ® Exposed!

Amazing Midpoints

In the sketch below, drag "pointP" and "pointW" to see different graphs. At any time, to see how the graph is created, right click the "a= " slider at the top and choose "animation on". To stop, right click the "a= " and deselect animation. To start over, click the little symbol at the top right corner of the sketch box. Note: you might have to click in the frame below to activate the sketch. For more, visit www.davemath.com

Saturday, December 14, 2013

My 1st GeoGebra "implant" into Blogger

Drag the point labeled "a" in the segment at the top of the sketch. I need to improve the sizes somehow so that an entire GeoGebra page will fit in the space provided in Blogger. Stay tuned. You may need to click inside the space below to start the graphic.

Friday, December 13, 2013

Parabolas are tough????

I submit the above two animated gifs (made in GeoGebra) for the sake of those who think that ellipses and parabolas are too complicated to understand.
The 1st gif, yielding an ellipse, only requires that the red segment and the blue segment always have the same combined length.
The 2nd gif, the parabola, only requires that the two dotted lines are always equal in length.
That's it. The rest comes from there.

Thursday, December 12, 2013

So Sine and Cosine are related? (or...have you ever seen the rain?)

Dynamic geometry can help show relationships that printed textbooks can only hint at.  If all you saw in this was that the getting from the cosine graph to the sine graph all you had to do was "shove" it to the right a bit, you'd be well on your way.

For the more utilitarian, here is a more well known device.

For more, see www.davemath.com

Wednesday, December 11, 2013

Do you Know or Remember?

Inside every triangle is imprisoned a very special circle. Did you know that? It is called the inscribed circle, and it is one of the many connections between circles and triangles.
A shipping question relates to this: if you were shipping a million sections of fragile pipe, would you consider a triangular-shaped box? If so, what type of triangle would be best?
When I was in school the closest I got to diagrams like above were those frozen in time and printed in books. Students can know learn about such things in a much more dynamic environment. Make sure they can and do!!!!
For more examples, go to www.davemath.com

Tuesday, December 10, 2013

Dynamic Geometry Opens Doors!

The sky is the limit as to what can be designed using the basics of GeoGebra.
Click here to see the actual file behind this graphic.
It is all basic Geometry (with just a smattering of trig so I could get flashing lights to work when the file was converted to an animated gif.

Software such as GeoGebra just be used as a math motivator as well as a math tool.

Monday, December 9, 2013

Dynamic Geometry is the Way to a Child's Brain!!

The above was created in GeoGebra some basic geometry such as midpoints, chords, rotation, with a dose of basic trig. Doable by ant middle-schooler in a short bit of time. (Exported as animated gif, then shrunk using Fireworks to reduce file size and make it fit here.)

Sunday, December 8, 2013


FOX just interrupted a moment of silence in honor of Nelson Mandela prior to the Eagles-Lions game for a Cialis ad!!!!!!

Saturday, December 7, 2013

Another new story about math in schools

"American 15-Year-Olds Lag, Mainly in Math, on International Standardized Tests" goes the title of the article in the NY Times of this past week. (see here)

Who knows what might be possible if the teachers and students had the opportunity and the teachers had the knowledge base and the resources.

A simple item such as below, a great motivating skill for a number of students, is not considered often. Since it is not testable, it is probably falling further outside the arena.

GeoGebra allows the user to manipulate images.
Here a simple 2-blade propeller was made to rotate using GeoGebra.
A simple task.

Check out http://www.angelfire.com/ny3/golfgolf/amtnys/AMTNYS2014/Plan2014.htm for other examples.