## Announcements

Exam #3 will be consist of (a) a set of take-home exercises that will be handed out Wed May 15, and (b) a set of in-class exercises on Mon May 20, when the take-home exercises will also be collected. The final exam is on Wed May 22.

I have reopened the relevant WebWork sets so that you can complete those exercises if you didn’t previously, and use them to review for Exam #3 and for the final exam. The following WebWork sets will be open until Wed May 22:

• ComplexNumbers
• Rational Expressions-Complex Fractions 1
• Rational Expressions-Complex Fractions 2
• Trigonometry-Right Triangles Trigonometric Ratios
• Trigonometry-Coordinate Plane Unit Circle

## Topics

We reviewed the definitions for the trig ratios for any angle, using the coordinate plane:

This led to the following chart of which trig ratios are positive vs negative in each quadrant:

This is sometimes termed “ASTC” (“All” are positive for an angle in quadrant 1, “Sin” is positive in quadrant 2, “Tan” is positive in quadrant 3, and “Cos” is positive in quadrant 4), and is sometimes taught with the phrase “All Students Take Calculus”):

We then used this to solve exercises from the WebWork and the Final Exam Review:

Finally, we introduced the unit circle, and explained how to use it to find the sin and cos for any angle shown–namely, look up the y-coordinate and x-coordinate (respectively) for the given angle: