Geogebra Tube Links for Mth221

Which quadrilateral am I? (Paul Yu)

https://www.geogebratube.org/student/m51987

Measured kitemaker (Paul Yu)

https://www.geogebratube.org/student/m19458

Triangle Inequality (Todd Smith)

https://www.geogebratube.org/material/show/id/78938

Interesting: Which of the three congruent triangles shown appears to have the most area? The most perimeter?

https://www.geogebratube.org/student/m19092

Sherman the Pig investigation (John Golden):

http://www.geogebratube.org/student/m170253

Minds on Mathematics - Storify

This is a record of the live-tweeting at @wendywardhoffer's #mindsonmath presentation at Kent ISD on Oct 2, 2014. In attendance and actively tweeting: @delta_dc, @ProfJonh, @RAnderson_Math.

Never Say Anything a Kid Can Say

Ever had one of these days?

If so, check out this article by Steve Reinhart (2000): “Never Say Anything a Kid Can Say!”.

For any fellow teacher-educators who view this, here's the home workshop I used to scaffold the discussion of this article, plus a few highlights from my students' post-workshop reflections.

Mr. Aion's Pledge to Improved Mathematics

I had to share this little gem I found on Year 2, Day 12, Justin Aion's blog, Relearning to Teach:

 

And so on his behalf and in his honor, I proudly present, "The Pledge to Improved Mathematics"! (also available in .png, .docx, and .pdf formats)

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Image credit: Justin Aion, http://whiteboardmath.blogspot.com/

From the Syllabus: My SBG Blurb

 It is getting on toward the end of the 6-week summer semester in college algebra, and I am once again thinking hard about my standards-based grading (SBG) implementation. As part of my reflection, I looked back at the relevant sections of the syllabus, where I spelled out in some detail what I thought my students needed to know about my SBG implementation this semester, including a bit about the philosophy, the implications, the expectations, and classroom procedures.

In event that some of it may be useful to other educators embarking on the SBG journey, and in the hope that others will share their ideas and insights, here are those relevant sections of the syllabus:

Transformations

Or: Is this the kind of problem where you can have more than one answer?

There are a select few topics in algebra that can get me tied up in knots. One of those is function transformations--you know, horizontal & vertical shifts, vertical stretches & compressions, and horizontal & vertical reflections--specifically, those that involve a multiple transformations.

Here's the task I got hung up on the other day:

The graph of a function f is shown. Sketch the graph of y = 2f(x+1) - 3.

On these types of tasks, it's not the transformations themselves that get me. There are three transformations at work here, and I can describe them easily enough:

1. Horizontal shift one unit left (because of the x+1).
2. Vertical shift three units down (because of the -3).
3. Vertical stretch by a factor of 2 (basically, double the y-values). 

The part that gets me hung up, at least when I have not done these kinds of problems in a while, is... in which order should I apply the transformations?

Because it makes a big difference! To illustrate, let's trace where the point (-2,1) ends up if we shift-then-double vs. double-then-shift:

• Shift-then-double: (-2,1) --left1--> (-3,1) --down3--> (-3,-2) --double y--> (-3,-4).
• Double-then-shift: (-2,1) --double y--> (-2,2) --left1--> (-3,2) --down3--> (-3,-1).

See? (-3,4) and (-3,-1).. we end up in two different spots.

This is not "the kind of problem you can have two different answers to" (Cathy Humphreys; clipped from one of the videos in this book).

GVSUMath Youtube Channel - Brief Tutorial

You can follow these instructions to search for a specific math topic on the GVSU Math YouTube channel. (Last updated: 6/24/2014)

1. Go to https://www.youtube.com/user/GVSUmath/ and click the icon to expand the search box.

2. Type in a few key words...

3. ...and hit Enter. With any luck, we will have a video on the topic. Enjoy!