The last few weeks of this summer have been filled with poster-making to spruce up my classroom and to make the walls more of a resource to my students. To determine what would be the most useful posters to make, I’ve been doing a lot of reflection about last year. One topic that I wish I had a public record/anchor chart style poster for was reference angles, which is covered in our Trigonometry unit in Algebra 2. I’ve been contemplating a lot about how I’d want it to look and had considered making an entire unit circle poster, but decided against it since I felt as if that promoted students to memorize all of the values.
I really want to get my students to the idea that they can derive as much or as little of the values as they desire. If they want, they can derive them all from scratch, and we discuss how to do this in class. We then talk about how if they feel more comfortable with memorizing them all so they can work quicker on a test/quiz, then they are free to do so as well. We then have the conversation about my own personal preferences: I memorize the sine and cosine values for the first quadrant. From there we can easily get tangent by dividing the sine value by the cosine value, and we can think about the properties on the coordinate plane to get the appropriate signs for any other angles. Most students choose to take my approach as well since it is a nice middle ground.
Here’s the PDF File – Reference Angles Poster. I sent mine over to my school’s print shop to be printed on 24″x36″ paper. You can print it on standard 8.5×11 paper if you select “Fit” or “Shrink Oversized Pages” on your prniter’s menu.
My last project for the summer will be making labels for 0, 90, 180, and 270 degrees with their corresponding sine and cosine values to be put around the wall clock in my classroom.
Happy Sunday! This marks 3 more weeks until I go back to school. How much time do you have?