### Whiteboard Doodles

#### May 6: Freedom from Cartesian Alignment

posted May 7, 2013, 10:39 AM by aaron.bradley@bvsd.org

#### April 29: Complex Number

posted Apr 29, 2013, 11:11 AM by aaron.bradley@bvsd.org

#### April: A couple of recent drawings

posted Apr 22, 2013, 11:16 AM by aaron.bradley@bvsd.org

 Trigonometry is useful for summing forces.  Gravity and propulsion combine to move this helicopter slowly forward.Illustration of the summation equation for sine.

#### April 9, 2013

posted Apr 9, 2013, 2:08 PM by aaron.bradley@bvsd.org

#### April 4, 2013

posted Apr 4, 2013, 2:41 PM by aaron.bradley@bvsd.org

#### February 13, 2013: Random

posted Feb 13, 2013, 3:51 PM by aaron.bradley@bvsd.org

 The cartoon well ran a bit dry lately, but here's a random doodle.

#### January 18: Celebrating Martin Luther King, Jr.

posted Jan 23, 2013, 4:37 PM by aaron.bradley@bvsd.org   [ updated Jan 23, 2013, 4:44 PM ]

 Part of Summit's celebration of Martin Luther King, Jr., was to construct, as a group, a 7'11" x 9'6" portrait of MLK Jr.  Over two days, each student wrote his or her dreams on several index cards and pasted them onto a grid according to color, together filling in 38 x 38 = 1444 pixels.The project was the idea of Ms. Drozda-Freedman (6th grade biology).  Monday evening, I used Gimp, Octave, and my mad math skillz to produce the 38 x 38 matrix attached below.  Tuesday evening, I constructed the grid and transferred the numbers.On Wednesday, Ms. Kuelthau (front office) supervised the effort of several volunteer parents to chop colored index cards in half to produce the right quantity of pixels.  Then over the next two days, Coach Vigil (PE) and Mr. Galvin (Acting Principal) helped the students paste in the pixels.  The result is, I think, a tribute to what a lot of people can accomplish together.

#### January 17, 2013: Geometric Meany

posted Jan 17, 2013, 11:14 AM by aaron.bradley@bvsd.org

 I guess I can't resist a bad pun.  We're studying geometric means in the context of right triangles, e.g., that the altitude to the hypotenuse is the geometric mean of the legs.

#### January 15, 2013: SASSy Triangles

posted Jan 15, 2013, 10:50 AM by aaron.bradley@bvsd.org

 Another cheap pun on the acronym for a theorem, Side-Side-Side for Similarity, which says that two triangles are similar if their corresponding sides are in the same proportion.  Of interest to the mathematician is the development of the similarity theorems from area.

#### January 14, 2013: Measure a Bunny to Measure a Giraffe

posted Jan 15, 2013, 10:48 AM by aaron.bradley@bvsd.org

 Another method of measuring tall things is to use a mirror: measure the distance from the mirror to each object and the height of the shorter one.  Apply AA to conclude the similarity of the two implicit triangles; then solve for the height of the taller object.

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