1/29/2010 - Intro to Trig

We started class by reviewing the “Francois and his Pedometer” packet. While we were going over the packet, we learned some new symbols that were introduced to us in #9-12. (E & Z). In trigonometry, the common variable is k. K is always defined as K E Z. This means that K is an element of Z, which is the set of all integers.

Next, we did an activity on Geogebra. We created angles, and manipulated them to learn about negative angles, and angles over 360 º.

















Ex. Negative angle (Left)
Ex. Angle > 360 º (Right)

One thing that we noted about the angles that we made was that when the initial ray of the angle was manipulated and moved around, the Arc length and Radius changed, but the radian’s value did not. When the terminal ray was moved the Arc length and the Radian value changed. These changes were also noted as proportional.

We also looked at a new packet of notes titled, “Introduction to Trigonometry Notes”. From the packet we learned:
The radian measure of one revolution is approximately 6.28 (2π)
The radian measure of one half of a revolution is approximately 3.14 (π)
Conversions between radians and degrees
Conversions of common radian values to degrees

Our homework for next class was practice problems in the book. Mr. O-Brien said that it was okay to only do a few from each section, if you felt that you understood the concept. Also, there are flashcards on Quizlet.com on common radian degree conversions.

Next Scribe: Julia