Friday, January 31, 2014

Every little bit helps

Last year's Geometry regents exam (NYS) question #22 brought this on

Thursday, January 30, 2014

Amazon, Amazon, Amazon...

Amazon is a big company. Hard to miss. Impossible to talk to.

Monday, January 27, I ordered an item. The site said the item would be in stock January 30, and I could expect delivery by February 4th. All is good. But...

Tuesday I found the same item in a local store (Target) and about 60% the cost compared to Amazon. I bought it there, and immediately, before I even left the store, went to Amazon on my iPhone to cancel the Amazon order. But behold, I see...

Strange to see it shipping now, when it isn't supposed to be in stock. But it says I can still request cancellation! So I do.  And then I see:
But it does say, and I quote " We're preparing this order for shipment. If you'd like to cancel item(s) from this order, check the Cancel Item box next to the item(s) and click "Request cancellation." We'll do our best to cancel the item(s) selected. "
So I do.
It doesn't get cancelled.
I have gone through this cycle twice a day Tuesday, Wednesday, today.
No cancellation. No shipping. Without shipping I cannot tell UPS or FedEx to return the item since I need a tracking number, which doesn't get issued until the item is sent.
Meanwhile, my credit card has been charged.
Could this be the knew "moneymaking" limbo?  There is no way I can get a refund until the item is sent and I can get it returned.
Oh, by the way, they say that my item which has still not been sent will arrive tomorrow.

Monday, January 27, 2014

Volumes by the Disk Method

This video is from a GeoGebra 3D file I created.
The file itself can be found here: http://www.geogebratube.org/material/show/id/78596

Thursday, January 23, 2014

Schooling as it really is

Thomas Friedman had an excellent article in the NY Times of January 19, 2014.
Rather than just quote him, here it is.

Tuesday, January 14, 2014

In my experimenting with GeoGebra 3D, I have found claims that exporting as animated gif works, yet that option has not been found on my version. Creating this gif required 3rd party recording followed by some editing using Fireworks.
Animated gifs are nice in that they can be seen where java cannot.

For more on dynamic geometry, see www.davemath.com

Monday, January 13, 2014

GeoGebra in 3D!

Starting to explore with Geogebra 5 beta in 3D. Animated gifs are different, as I have to record them using other software.

It's a beginning, though.

For more animated geometry, visit www.davemath.com

Monday, January 6, 2014

Cinderella does Geometry too!

This animated gif was originally created in Cinderella and then recorded as a gif by LICEcap .

I have begun to explore Cinderella so as to be able to compare it with Geogebra and Geometer's Sketchpad.

For more examples of dynamic geometry, check out www.davemath.com

Saturday, January 4, 2014

Sliding Ladders and Fancy Math

An astroid (not asteroid) can be considered a complicated shape related to hypocycloids and heavy in trig, but it can be introduced using a "sliding ladder". The black segment represents a ladder which slides down a wall. By tracking its path, we generate one cusp of an astroid.
For more on dynamic geometry, visit www.davemath.com
Click on the picture to get the underlying geoGebra file!